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PubMed2001

Computer-based diagnostic support systems in histopathology: what should they do?

In many fields in histopathology diagnosis making is notoriously difficult. We explored the diagnostic process in the area of CL and related disorders. The field of cutaneous lymphomas (CL) and borderline lesions is complex and representative for the type of diagnostic problems encountered. A review of diagnostic support systems in diagnostic pathology revealed that the usefulness of these systems has been disappointing. We contribute this to the fact that these systems target only part of the diagnostic process. A tentative model of diagnosis making in pathology is presented. This model assumes a two-step process, from observation to feature recognition and from features to diagnosis. In a retrospective study of existing skin biopsy pathology reports we assessed detail and scope of the histological descriptions. In a second, prospective study, a pathologist panel described a set of 16 skin biopsies using a standard set of descriptors. The retrospective study showed a large variability in the nature and details of described features, whereas the prospective study showed lack of consensus regarding both feature descriptions and diagnostic category. Both studies provide an indication that lack of consensus in feature recognition may be an important contributor to lack of consensus at the diagnostic level. Diagnostic expert systems target the step from feature to diagnosis. Evidently different input into such systems produces different output. We conclude that support of the feature recognition step can contribute to better diagnostic consensus because of more uniform interpretation of observations.

Biopsy↗
PubMedDate not supplied

[Chest pain syndrome in normal or non-diagnostic conventional ECG at the emergency service. Assessment with myocardial perfusion (SPECT) and ventricular function (Gated-SPECT)].

The arrival of a patient with chest pain syndrome (precordial) to the emergency represents a diagnostic challenge for the physician. Around 6 million persons are seen each year at the Emergency units in the USA. More than half of the patients are admitted for their cardiac evaluation. Its cardiac origin is confirmed in 10 to 15%, and about 15% of them develop myocardial infarction. However, 5 to 10% of patients are dismissed and develop myocardial infarction during the next 48 h. The diagnosis of the infarct is inadvertent and/or patients is not hospitalized in 2 to 8%. The mortality rate is duplicated in none hospitalized patients. Frequently, a conservative observation conduct and/or diagnostic expectation is taken, with the consequent saturation of the intensive care unit that looses its critical character and avoids quick mobilization of the patient with an increase in costs. The clinical judgment, a meticulous clinical history, and careful physical examination play a key role in the differential diagnosis of the precordial pain syndrome; however, pain can be atypical, absent or manifest as an equivalent of pain, which does not exclude the diagnosis of myocardial infarction or ischemia. Likewise, chest pain in the presence of a normal conventional ECG at rest, non-diagnostic or with minimal variations, does not rule out the possibility of a coronary obstruction and does not mean that the pain is not of coronary origin. Other characteristics of the ECG, such as T wave and ST segment alterations, bundle branch block (BBB), LV hypertrophy, interpretation discrepancies, can pose doubts or mistakes in the diagnosis. Although its diagnostic information is essential, other non-invasive laboratory tests are needed, such as the treadmill stress ECG, serial bioenzymatic markers, and myocardial perfusion scintigraphy (SPECT and Gated-SPECT) at rest or under physical or pharmacologic stress. The advantages and disadvantages of the stress ECG, the echocardiography, magnetic resonance and PET are mentioned. The advantages of the SPECT and Gated-SPECT in the diagnosis and prognosis are: 1) great diagnostic objectivity; 2) high sensitivity and specificity; 3) diagnosis does not depend on evolution time of the ischemia and/or infarction, since SPECT diagnoses the initial primary modifications of ischemia; 4) diagnosis is achieved within the established limit of time, in less than 4 to 6 hours. The designed protocols allow to obtain the diagnosis between 30 min and 1:30 h; 5) assesses the myocardium at risk; 6) stratifies the risk and prognosis; 7) defines the site and 8) the involved coronary artery(les); 9) provides the functional significance of the anatomic obstruction; 10) quantifies the ventricular function, i.e., ejection fraction, systolic and diastolic volumes, systolic thickening, ventricular failure signs; 11) provides three-dimensional visualization of the mobility of the left ventricular wall; 12) diagnoses simultaneously the associated presence of ischemia and/or infarction of the right ventricle; 13) its high negative predictive value allows to dismiss immediately and with a great safety margin those patients in whom SPECT revealed normal perfusion; 14) costs are reduced without adversely compromising the safety of the patients. We describe the algorithm used as guideline for the early diagnosis in the presence or absence of ischemic heart disease in the patient with precordial or chest pain syndrome with normal or non-diagnostic ECG at arrival to the emergency ward. It is necessary to modified the clinical educational patterns and to revaluate the advantages and limitations of the clinical history, physical exploration, as well as of the conventional ECG at rest and other diagnostic methods used specifically in relation to the chest pain syndrome with a normal or non diagnostic conventional ECG. SPECT and Gated-SPECT scintigraphy is considered as the best individual and isolated non-invasive test for the diagnostic solution of the precordial syndrome at the Emergency Unit.

Algorithms↗
PubMed2004

[Traditional and innovative diagnostic tools: when and why they should be applied].

The development of new technological methods surely improves the quality of the Diagnostic Services in Parasitology offered to the National Sanitary Service, however, cost and simplicity have not to be neglected, even when the prime consideration is efficiency. Moreover, the mere fact that something can be done by one of these new approaches does not mean that it should be done that way or that it is most cost-effective to do it that way. A review of diagnostic tools in Parasitology is proposed, to evaluate when and why each of them should be applied. Traditional procedures for the diagnosis of parasitosis are only based on the "direct" recovery and recognition of the parasite, with the microscope as main tool and few other instruments as co-operator. The innovative procedures, recently adjusted on the basis of new scientific knowledge and made possible by the development of the laboratory instrument weapons, can evidence the parasites both directly and indirectly. If it is obvious that the direct identification of a pathogen is more reliable than that indirect, is not so evident what is the most useful direct method, and when it would be better to use indirect diagnostic tools. Advantages and disadvantages of each procedure, cost as well as the purpose of the test (diagnosis, post-treatment, research), and the general condition in which the test have to been applied must be taken into account when we are choosing. In general, we can say that the rationale for their use can be summarised as follows: 1) The macroscopic/microscopic analysis of samples is always recommended (with the exception of samples coming from tissues that need surgery). This "old" procedure allows the identification in 20 minutes of all the parasites present in mixed infections, and the evaluation of the parasite load. It is a cost-effective method which relies ultimately on the skill of the observer to detect and identify parasite stages; 2) Parasite antigen detection is an innovative and expensive immunological diagnostic, which can suffer of sensitivity and specificity. It could be useful to directly diagnose "occult" infections; 3) Parasite DNA/RNA direct detection is an innovative, sensitive and specific procedure, which can also identify sibling species. It is expensive, therefore its use is restricted to reference laboratories; 4) Host antibody detection is an innovative indirect tool to evaluate the presence of a parasite by means the evaluation of the host response to infection. It can suffer of sensitivity and specificity, and the interpretation of the test results may be difficult. It could be applied as first step to evaluate the presence of tissue parasites, whose direct diagnosis would require surgery. Some tests can be performed in well-equipped laboratories; other tests are available through research laboratories. The specimens, appropriately collected and preserved, have always to be processed in security for potential risk of infection hazard, and submitted to tests appropriate to the laboratory's goals, where, therefore, field and research diagnostic tools shouldn't be applied. The test selected for routine use has to be chosen taking into account value and limitations of each method. Reduction in excessive and often unnecessary testing is mandatory, and therefore it is critical for the clinical Parasitology to perform relevant testing while maintaining appropriate quality. To date, the microscopic analysis of samples is the only direct method that allows all identifications in short times, at a reduced cost, independently from geographical origin and peculiar status of the patient. It has to be regarded as the first step in diagnostic procedures for all laboratories. Some molecular techniques have greater sensitivity than traditional methods, but at least at the present time, their costs may well preclude their routine use. It is difficult to know, exactly, where diagnostic Parasitology will be moving in the next few years, although many soothsayers feel very strongly that the area of molecular diagnostics will replace more traditional means. It is also possible that immunological or perhaps cytometric procedures will replace our more standard diagnostic approach; nevertheless they will continue to remain oddities on the outside of the general practice and be confined to a few reference laboratories. As far as semi-automated or automated instruments and robotics-based techniques, they are useful when large numbers of the same test are performed. Supposing that they will enter in our laboratory, that will happen in central facility rather than in each local facility. So, the great interest in using new technological methods to solve old problems probably will have to be seen in the right perspective.

Animals↗
PubMedDate not supplied

Pain and the diagnostic process: conceptions and misconceptions.

Pain may be considered a diagnostic alarm that acknowledges but usually fails to determine the etiology of a particular clinical problem. Diagnosis thus involves the extraction of additional information from a patient in order to determine rational bases for treatment. The process is ill-defined and fraught with error unless the diagnostician is aware of all and only the relevant diagnostic alternatives. This list of alternatives plus an appreciation of the likelihood of each possible diagnostic outcome determines the fastest rate that diagnostic information can be processed by any system in the absence of unpredictable events called noise. Human diagnosticians must be fluent in the "language" used to convey the desired information if performance is to be optimized. In general this involves restructuring the diagnostic task into smaller pieces which are easier to digest perceptually. One way to accomplish this is to ignore or eliminate patterns which are either irrelevant or occur so rarely (or so commonly) that they usually have negligible impact on diagnostic performance. The utility of a diagnosis is determined ultimately by the degree to which it influences the health and well-being of both the patient and society at large. Hence, the consequence of a particular disease may offset the low diagnostic yield per examination resulting from a low or high prevalence of the disease. When diagnostic patterns are limited by ignorance to only signs and/or symptoms such as pain, the diagnostic process loses its meaning and treatment decisions are compromised necessarily by uncertainty.

Diagnosis, Differential↗
PubMedDate not supplied

Service program diagnostics and decision support technology for improving health technology service efficiency and productivity.

Our in-depth survey of both the state of the art and the results of application, implementation, and rollout of problem resolution diagnostics in control help desks and field service clearly shows the potential of online remote diagnostics technology (Figure 9) to improve service force productivity and efficiency and to make more effective use of service resources (people and parts). Our survey of the current and planned future expenditures for diagnostics used in field service clearly indicates that the overall service diagnostics market is currently sizable, in the range of $2 billion as of 1997, and is projected to grow to approximately $2.6 billion by 2000. This current expenditure and growth will occur primarily in the electronics arena, but there are still substantial development and application investments occurring in both electromechanical and mechanical areas. We believe that the pace of investment will fall off as the service industry shifts from development and experimental research to the application and rollout of standard off-the-shelf technology. Thus, the overall pattern of the diagnostics market indicates a continuing increase in expenditures by the field service industry for electronics-oriented service diagnostics and some increase with respect to use of this technology in electromechanical and mechanical applications. The application and use of diagnostics technology will also be affected by the ability of the field service management community to recognize the need to search for an optimum as opposed to a feasible solution to dispatch, assignment, call screening, call avoidance, and logistics deployment. The further rollout of affordable wireless communications technology such as Ardis and Ram mobile and the new cellular-based CPDP technology, coupled with the increased availability of inexpensive wireless-based laptops, portables, and CD-ROM-based problem resolution and diagnostics technology clearly shows the value of this technology in improving service productivity, efficiency, and profitability. As we move from very expensive academically and research and development-oriented diagnostics applications to the purchase and use of off-the-shelf software and predeveloped knowledge bases, it is clear that this technology will be broadly applied.

Cost-Benefit Analysis↗
PubMed1999

[Validation of a diagnostic scoring system (Ohmann score) in acute appendicitis].

A diagnostic scoring system, recently published by Ohmann et al. in this journal, was validated by analyzing the clinicopathological data of a consecutive series of 2,359 patients, admitted for suspicion of acute appendicitis. The results of the scoring system were compared to the results of clinical evaluation by junior (provisional) and senior surgeons (final clinical diagnosis). To assess the diagnostic ability of the score, the accuracy and positive predictive value were defined as the major diagnostic performance parameters; the rate of theoretical negative laparotomies and that of diagnostic errors served as the major procedural performance parameters. Of 2,359 patients admitted for suspected acute appendicitis, 662 were proven to have acute appendicitis by histology, for a prevalence of 28%. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the provisional clinical diagnosis were 0.50, 0.94, 0.77, 0.83, and 0.82; 0.93, for the score 0.63, 0.93, 0.77, 0.86 and 0.84, and for the final clinical diagnosis 0.90, 0.94, 0.85, 0.96, and 0.93, respectively. Of the main diagnostic performance parameter, the accuracy of the score was significantly better than that of provisional clinical diagnosis (P < 0.05, chi 2 test). The score yielded a rate of negative appendecomies and laparotomies of 14.3 and 12.3%. With respect to the rate of overlooked cases of acute apendicitis, the score demonstrated a superior performance, with only 6 cases missed (0.9%). However, the number of patients with acute appendicitis, including those with perforated disease, who were not identified by the score, was almost four times that of the final clinical diagnosis (245 vs 63). With regard to the main procedural performance parameter, the score resulted in a significantly smaller number of diagnostic errors than the provisional clinical investigator (P < 0.05, chi 2 test). The results of this study indicate that the diagnostic scoring system might be helpful when experienced investigators or additional diagnostic modalities such as ultrasonography are not available. It may therefore be of value in the preclinical evaluation of patients with suspected acute appendicitis and may be instrumental as a quality control tool and in clinical guidelines.

Acute Disease↗
PubMed1986

Effect of restraints on diagnostic approaches to abdominal pain and weight loss.

To examine the effects of restraint on the diagnostic process, 25 physicians were urged to be as economical as possible when requesting diagnostic tests for case report simulations of nine patients who had previously been hospitalized with abdominal pain and weight loss. The results of the tests correctly changed the physicians' initial diagnoses, increased their diagnostic confidence, and led to appropriate management decisions. When restrained, individual physicians needed only 3.0 (1.7 to 4.1) diagnostic procedures per patient to reach management decisions, whereas 6.1 (3.0 to 11) diagnostic procedures had actually been performed. Diagnostic approaches were so diverse, however, that the number of procedures collectively requested by randomly assembled "teams" consisting of four to five "economical" physicians equaled the number of procedures actually performed. Moreover, 20 percent of the procedures requested by "economical" physicians were invasive compared with only 7 percent of those actually performed. These findings suggest that, without uniform diagnostic approaches, "team" management may increase testing despite restraint by individual physicians. Moreover, quests for economy may increase invasive diagnostic testing.

Abdomen↗
PubMed2006

Diagnostic adequacy and accuracy of fine needle aspiration cytology in neck lump assessment: results from a regional cancer network over a one year period.

AIM: To establish the diagnostic accuracy and adequacy of fine needle aspiration cytology (FNAC) within a regional cancer network, and to determine what service improvements may be required to allow successful implementation of an FNAC-based, 'one-stop' head and neck clinic, as proposed by the current National Institute for Clinical Excellence guidelines. MATERIALS AND METHODS: The Sussex cancer network serves a population of 1,200,000 and contains five hospitals within three acute trusts. In 2004, an audit was undertaken retrospectively to examine the diagnostic adequacy and accuracy of head and neck FNAC across the network. Comparisons were then made with the results of subsequent relevant surgery. For the purposes of the audit, FNAC was subdivided into three main groups: salivary gland, thyroid gland and neck node. As part of the data analysis, we also noted the clinical source of the FNAC and whether it was performed blind or under image guidance. RESULTS: In 2004, 712 FNAC procedures were undertaken in 647 patients, 276 of whom underwent subsequent surgery. Fine needle aspiration cytology was non-diagnostic in 52 per cent of patients in the neck node group, in 50 per cent in the salivary gland group and in 30 per cent in the thyroid group. With these non-diagnostic results removed, statistical analysis was performed on data from those patients who had undergone both FNAC and subsequent surgery. This gave a sensitivity of 89 per cent and a specificity of 57 per cent in the neck node group, a sensitivity of 64 per cent and specificity of 100 per cent in the salivary gland group, and a sensitivity of 62 per cent and specificity of 86 per cent in the thyroid group. Diagnostic problems with FNAC were noted, particularly in the differentiation of reactive nodal hyperplasia from lymphoma and in diagnosing follicular thyroid lesions. Ultrasound guidance was used in 50 per cent of the thyroid FNAC procedures but in only a minority of patients in the neck node and salivary gland groups. CONCLUSION: This audit demonstrated widespread diagnostic difficulties associated with head and neck FNAC in a large patient sample. It is likely that these problems will be mirrored in other cancer networks. In order for one-stop head and neck clinics to succeed, the non-diagnostic rate of FNAC in particular must be minimised. There are strategies to enable this, depending on local resources, including increased access to cytologists or cytology technicians, diagnostic ultrasound, image guidance for FNAC and the use of ultrasound-guided core biopsy.

Biopsy, Fine-Needle↗
PubMed2005

[Differences in the extent of diagnostic procedures after acute stroke in patients treated in departments of neurology, internal medicine and geriatric medicine].

BACKGROUND AND PURPOSE: In Germany, data about variations in acute stroke treatment between different facilities are lacking. The aim of the present study was to compare the extent of diagnostic procedures for acute stroke between departments of neurology, internal medicine, and geriatric medicine. METHODS: Stroke patients admitted to hospitals cooperating within the Westphalian Stroke Register between January 1, 2000 and December 31, 2001 were analyzed. Forty-two hospitals participated in the study including 24 departments of neurology, 13 of internal medicine, and 5 of geriatric medicine. The register is based on a standardized data assessment including sociodemographic and clinical characteristics of the patient, in the acute phase, as well as diagnostic and treatment procedures, complications, and status at discharge. The performance of brain imaging, Doppler, and echocardiography was defined as diagnostic standard for diagnosis and etiological classification of ischemic stroke. RESULTS: A total of 12,232 stroke patients were included. Mean age was 72 years, 49 % were men. In general, diagnostic procedures were administered more often in neurological departments compared to departments of internal or geriatric medicine. In all participating hospitals, the application of diagnostic techniques was less frequent in older patients. The defined diagnostic standard was performed more often in those neurological departments providing acute stroke unit services compared to neurological departments without stroke unit services. CONCLUSION: Our study detected variations in the extent of diagnostic procedures in acute stroke between different medical disciplines. However, further studies are required to clarify whether a more frequent performance of diagnostic techniques yields relevant therapeutic consequences.

Acute Disease↗
PubMed2006

Diagnosing major depressive disorder VII: family history as a diagnostic criterion.

Eliciting information about a patient's family history is a component of a standard diagnostic evaluation. Since depression runs in families, a question arises as to whether family history information should be considered when diagnosing depression. The text of DSM-IV indicates that a family history of a mood disorder should sometimes be considered when trying to distinguish between major depressive disorder and other conditions such as catatonic schizophrenia. The questions posed herein are how well family history of depression performs as a diagnostic criterion, and how its performance compares with the DSM-IV symptom criteria. One thousand eight hundred psychiatric outpatients were evaluated with a semistructured diagnostic interview as part of a research assessment infrastructure that has been embedded in the Rhode Island Hospital Department of Psychiatry outpatient practice. Family history diagnoses were based on information provided by the patient. The interview followed the guide provided in the Family History Research Diagnostic Criteria. We constructed a continuum of family history morbidity based on the number of first-degree family members with a history of depression and whether the family member was treated for their depression. Thus, we determined the presence or absence of the family history diagnostic criterion in different ways. Family history information was collected on 9763 first-degree relatives of 1776 patients. The sensitivity of the family history criterion was lower than each of the symptoms. Based on the broadest definition of the family history variable, the specificity was also lower than all other symptoms. Based on the narrowest definition (two or more family members who were treated for depression), the specificity was higher than all of the symptom criteria though sensitivity dropped to 15%. Overall, as a diagnostic criterion, a family history of depression did not perform as well as the DSM-IV symptom criteria. Consistent with the familial nature of depression, the family history variable performed better as a diagnostic criterion when considering diagnosis from a lifetime, rather than a current, perspective. This has implications for the future consideration of genetic markers as diagnostic criteria.

Adult↗
PubMed2000

Dementia diagnostic guidelines: methodologies, results, and implementation costs.

OBJECTIVE: To facilitate the diagnostic process for dementia. Five guidelines and four consensus statements on specific diagnostic recommendations, specialist referral recommendations, and costs of recommended diagnostic procedures were compared and summarized. DATA SOURCES AND SELECTION: A MEDLINE search from 1984 to 1999 and queries to experts yielded 14 guidelines and consensus statements that addressed the diagnosis of dementia. Only nine documents which had national or international scopes were reviewed. METHODS: Comparisons were made on the specific diagnostic criteria for patient history, clinical examination, functional assessment, laboratory tests, neuroimaging, and other diagnostic tests, as well as specialist referral recommendations and costs for the recommended diagnostic procedures. The first three authors reviewed independently each document and completed a table on specific recommendations in each document. To settle disagreements about specific recommendations, they discussed them until they reached a consensus. To interpret the intent of vague statements, they used their best judgment. RESULTS: The documents differed in content, recommendations, and development methodology. They were based on either expert opinion or scientific evidence, or both. Although the nine documents were nearly unanimous in several recommendations, including assessing the presenting problem, taking a medical history, conducting physical and neurological examinations, and assessing the patient's mental and cognitive status, considerable differences in recommendations were common. Such differences led to large differentials in the estimated costs (range, $190 to $2,001) for recommended diagnostic assessments. CONCLUSIONS: A systematic approach to diagnostic recommendations for dementia may induce greater consistency among guidelines and consensus statements. The current approach leads to considerable variability in recommendations and estimated costs.

Consensus Statements as Topic↗
PubMed2025

Hierarchical integration of mNGS, PCR, and other conventional methods for precision TB diagnostics.

UNLABELLED: This study systematically compared the diagnostic accuracy of seven assays for detecting the Mycobacterium tuberculosis complex, including metagenomic next-generation sequencing (mNGS), droplet digital polymerase chain reaction, real-time quantitative polymerase chain reaction, EasyNAT MTC, GeneXpert MTB/RIF, interferon-gamma release assay (IGRA), and acid&#x2012;fast staining (AFS). We try to select appropriate combinations of tuberculosis (TB) detection methods for regions with varying levels of medical resources, based on sensitivity, cost-effectiveness, and operational feasibility. A retrospective analysis was conducted on 141 samples collected from patients with suspected active TB at The First Affiliated Hospital of Sun Yat-sen University between April 2022 and April 2024. Among these samples, there were 100 cases assigned to the case group and 41 cases to the control group, based on the tuberculosis diagnostic criteria. Historical data for Xpert, IGRA, and AFS were collected, and parallel experiments using mNGS, droplet digital PCR (ddPCR), real-time quantitative polymerase chain reaction (RT-qPCR), and EasyNAT were conducted on all samples. Diagnostic performance was evaluated by comparing it with the final clinical diagnoses. Sensitivity, specificity, positive predictive value, negative predictive value, and receiver operating characteristic (ROC) curve analysis were conducted, along with DeLong tests for statistical comparison. Compared with the final clinical diagnosis, mNGS demonstrated the highest sensitivity (100%), followed by IGRA (79.2%), EasyNAT (79.1%), RT-qPCR (78.0%), ddPCR (75.8%), Xpert (75.3%), and AFS (16.7%). The specificity was 100% for both Xpert and AFS, followed by ddPCR (97.6%), RT-qPCR (95.1%), EasyNAT (92.7%), IGRA (72.7%), and mNGS (75.6%). ROC analysis revealed a significantly greater area under the ROC curve for mNGS (0.878) than for ddPCR (0.817, P = 0.031). DeLong tests revealed statistically significant differences in diagnostic performance between mNGS and ddPCR (P < 0.05) and between IGRA and AFS (P < 0.01). mNGS uniquely identified the pathogens involved in co-infection and quantified pathogen-specific sequencing reads. Through a comprehensive evaluation of the diagnostic efficacy, cost-effectiveness, and timeliness of tuberculosis detection methods, we propose corresponding combinations of TB testing approaches for regions with different healthcare resources. For undeveloped regions with limited resources, a combination of AFS +EasyNAT + chest X-ray is recommended. Primary care facilities may additionally employ IGRA + RT-qPCR. Intermediate-level hospitals can incorporate Xpert MTB/RIF for drug resistance testing, while tertiary hospitals or specialized centers should, on the basis of these fundamental tests, utilize mNGS for diagnosis and ddPCR for therapeutic monitoring in patients with complex mixed infections. IMPORTANCE: This study is the first to comprehensively evaluate the diagnostic efficacy, cost-effectiveness, and timeliness of seven TB detection methods in a single-center cohort. Our findings provide actionable solutions for optimizing TB diagnostics in diverse healthcare ecosystems, aligning with the WHO's End TB Strategy to ensure equitable access to rapid diagnostics.

Humans↗
PubMed2006

Evidence of bias and variation in diagnostic accuracy studies.

BACKGROUND: Studies with methodologic shortcomings can overestimate the accuracy of a medical test. We sought to determine and compare the direction and magnitude of the effects of a number of potential sources of bias and variation in studies on estimates of diagnostic accuracy. METHODS: We identified meta-analyses of the diagnostic accuracy of tests through an electronic search of the databases MEDLINE, EMBASE, DARE and MEDION (1999-2002). We included meta-analyses with at least 10 primary studies without preselection based on design features. Pairs of reviewers independently extracted study characteristics and original data from the primary studies. We used a multivariable meta-epidemiologic regression model to investigate the direction and strength of the association between 15 study features on estimates of diagnostic accuracy. RESULTS: We selected 31 meta-analyses with 487 primary studies of test evaluations. Only 1 study had no design deficiencies. The quality of reporting was poor in most of the studies. We found significantly higher estimates of diagnostic accuracy in studies with nonconsecutive inclusion of patients (relative diagnostic odds ratio [RDOR] 1.5, 95% confidence interval [CI] 1.0-2.1) and retrospective data collection (RDOR 1.6, 95% CI 1.1-2.2). The estimates were highest in studies that had severe cases and healthy controls (RDOR 4.9, 95% CI 0.6-37.3). Studies that selected patients based on whether they had been referred for the index test, rather than on clinical symptoms, produced significantly lower estimates of diagnostic accuracy (RDOR 0.5, 95% CI 0.3-0.9). The variance between meta-analyses of the effect of design features was large to moderate for type of design (cohort v. case-control), the use of composite reference standards and the use of differential verification; the variance was close to zero for the other design features. INTERPRETATION: Shortcomings in study design can affect estimates of diagnostic accuracy, but the magnitude of the effect may vary from one situation to another. Design features and clinical characteristics of patient groups should be carefully considered by researchers when designing new studies and by readers when appraising the results of such studies. Unfortunately, incomplete reporting hampers the evaluation of potential sources of bias in diagnostic accuracy studies.

Clinical Trials as Topic↗
PubMed2001

Newborns with suspected occult spinal dysraphism: a cost-effectiveness analysis of diagnostic strategies.

OBJECTIVE: To assess the clinical and economic consequences of different diagnostic strategies in newborns with suspected occult spinal dysraphism. METHODS: A decision-analytic model was constructed to project the cost and health outcomes of magnetic resonance imaging (MRI), ultrasound (US), plain radiographs, and no imaging in newborns with suspected occult spinal dysraphism. Morbidity and mortality rates of early versus late diagnosis of dysraphism and the sensitivity and specificity of MRI, US, and plain radiographs were obtained from the literature. Cost estimates were obtained from a hospital cost accounting database and from the Medicaid fee schedule. RESULTS: We found that the choice of imaging strategy depends on the underlying risk of occult spinal dysraphism. In low-risk children with intergluteal dimple or newborns of diabetic mothers (pretest probability: 0.3%-0.34%), US was the most effective strategy with an incremental cost-effectiveness ratio of $55 100 per quality-adjusted life year gained. For children with lumbosacral dimples, who have a higher pretest probability of 3.8%, US was less costly and more effective than the other 3 strategies considered. In intermediate-risk newborns with low anorectal malformation (pretest probability: 27%), US was more effective and less costly than radiographs and no imaging. However, MRI was more effective than US at an incremental cost-effectiveness of $1000 per quality-adjusted life year gained. In the high-risk group that included high anorectal malformation, cloacal malformation, and exstrophy (pretest probability: 44%-46%), MRI was actually cost-saving when compared with the other diagnostic strategies. For the intermediate-risk group, we found our analysis to be sensitive to the costs and diagnostic performances (sensitivity and specificity) of MRI and US. Lower MRI cost or greater MRI diagnostic performance improved the cost-effectiveness of the MRI strategy, whereas lower US cost or greater US diagnostic performance worsened the cost-effectiveness of the MRI strategy. Therefore, individual or institutional expertise with a specific diagnostic modality (MRI versus US) may influence the optimal diagnostic strategy. CONCLUSIONS: In newborns with suspected occult dysraphism, appropriate selection of patients and diagnostic strategy may increase quality-adjusted life expectancy and decrease cost of medical work-up.

Cost-Benefit Analysis↗
PubMed2005

Iatrogenic harm caused by diagnostic errors in fibrodysplasia ossificans progressiva.

BACKGROUND: Little is known about diagnostic errors for a disease worldwide. Such errors could alter the disease's natural history, especially if unwarranted interventions cause irreversible harm. Fibrodysplasia ossificans progressiva (FOP), a rare, autosomal dominant genetic disease characterized by episodes of permanent heterotopic ossification of soft tissues, occurs worldwide without racial, ethnic, or geographic predilection. There is no effective treatment, and soft-tissue trauma (eg, biopsies, surgical procedures, intramuscular injections, or mandibular blocks for dental procedures) and viral illnesses are likely to induce episodes of rapidly progressive heterotopic ossification, with resultant permanent loss of motion in the affected area. Accurate diagnoses can be made on the basis of the clinical findings of tumor-like swellings on the head, neck, back, or shoulders and characteristic short great toes with hallux valgus-like malformations and missing interphalangeal joints. On the basis of conversations with numerous individuals with FOP, we suspected that diagnostic errors with FOP are common and often associated with inappropriate and harmful diagnostic and therapeutic procedures. OBJECTIVE: To document the frequency of diagnostic errors with FOP and complications resulting from misdiagnoses. DESIGN: A questionnaire requesting detailed demographic, diagnostic, and treatment information was sent to all 269 patient-members of the International FOP Association; the sampling frame included > 90% of all known FOP patients worldwide. We received 138 replies (51% response) from 25 countries. The age range was 2 to 71 years; there were 78 female subjects and 60 male subjects. In addition, to assess the availability and adequacy of information about FOP, we reviewed 184 English-language textbooks in relevant specialties published in the past 20 years. RESULTS: Incorrect diagnoses were given initially to 87% of individuals with FOP. This astonishing rate of diagnostic errors occurred worldwide, regardless of ethnicity, geographic background, or misdiagnosing physician's specialty. The most common incorrect diagnosis was cancer (32%). The mean period from the onset of symptoms to correct diagnosis was 4.1 years, and the median number of physicians consulted before the correct diagnosis of FOP was 6. For 67% of patients, unnecessary invasive procedures (biopsies) were performed; 68% received inappropriate therapies. Forty-nine percent of all patients reported permanent loss of mobility resulting from invasive medical interventions that caused posttraumatic ossification. Notably, only 8% of the 184 textbooks that were reviewed contained adequate descriptions of FOP, including the caution that trauma can accelerate the process of heterotopic ossification. CONCLUSIONS: Diagnostic errors and inappropriate medical procedures, which may lead to permanent harm, can alter the natural history of a disease. In FOP, the astonishing rates of diagnostic errors and inappropriate invasive medical procedures likely result from lack of physician awareness because of failure of information transfer.

Adolescent↗
PubMed2004

[Characterization of diagnostic tests].

The primary aim of the diagnostic process is to establish the prevalence or probability of a disease given a certain clinical picture. A diagnostic test (DT) could be considered as every piece of information obtained from a patient. The DT can be done with technical devices, medical examinations or questionnaires. The DT offers information that allows us to classify patients according to a different probability to be sick. The operative validity of a test can be done in terms of diagnostic accuracy. It means the ability to truly classify a patient in the right clinical situation. Diagnostic accuracy is the quality of the information provided by a test (sensitivity, specificity). Diagnostic usefulness of a DT is the practical value of the information provided that does not have to coincide with the diagnostic accuracy. The operative validity allows us to classify the patients into different groups with different diagnostic, prognostic or therapeutic implications. The predictive value of a DT depends on its accuracy and the prevalence of the disease in the setting where the diagnostic process is to be made. Decision making with the information provided by the DT makes it necessary to consider the consequences of a false result.

Bayes Theorem↗
PubMed1992

[Acute abdominal pain--standardized findings as diagnostic support. Results of a prospective multicenter intervention study and testing of a computer-assisted diagnosis system].

Despite powerful diagnostic tools (e.g. ultrasound, special laboratory investigations), the diagnosis of acute abdominal pain is still a considerable problem. Several studies in the UK have shown that the diagnostic accuracy can be improved by structured and standardized history taking and clinical examination and by computer-aided diagnosis. In the framework of a concerted action of the European Community we have conducted a prospective multicenter interventional trial comparing two consecutive phases: a) a baseline phase in clinical routine without additional intervention, b) a test phase with structured and standardized history and clinical examination (questionnaire, documentation programme). In addition, a computer-aided diagnostic system developed in the UK was applied to the cases in the test phase. Outcome criteria were the diagnostic accuracy of the initial and the final examiner, the perforated appendix rate, the negative appendectomy rate, the negative laparotomy rate and the rates of diagnostic errors with missing indication to operation and of delayed urgent operations. No differences could be found between the phases with respect to the outcome criteria. In the baseline phase (test phase) diagnostic accuracy was 59% (59%), diagnostic accuracy after investigation (senior examiner) was 77% (78%), perforated appendix rate was 11% (16%), negative appendectomy rate was 13% (15%), negative laparotomy rate was 7% (8%), the rate of missed urgent indications to operation was 1.1% (1.9%) and the rate of delayed urgent operations was 3.4% (2.4%). Major differences between the centers were recorded. Computer-aided diagnosis resulted in a diagnostic accuracy of 51%. The introduction of structured and standardized history taking and clinical examination has not brought any improvement of the good results in clinical routine. It is doubtful, whether existing systems of computer-aided diagnosis are able to significantly decrease the still remaining error rate of 20%.

Abdomen, Acute↗
PubMed1995

Brief diagnostic interviews (SDDS-PC) for multiple mental disorders in primary care. A pilot study.

OBJECTIVE: To pilot test the feasibility and validity of new, brief, structured, physician-administered diagnostic interviews for six mental disorders in primary care patients identified from a patient-completed screen. DESIGN: Comparison of the new diagnostic interviews with the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition, version P (SCID-P), administered independently by a mental health professional. SETTING: Three Rhode Island family practices and a South Carolina family medicine residency. SUBJECTS: Consecutive patients of either sex, aged 18 to 70 years, who were able to read and write English were eligible for screening; 775 patients completed the screen. Of these, 246 screened positive for at least one disorder and received at least one module. Of these, 158 received a SCID-P interview. RESULTS: The diagnostic interviews were found useful by all 16 participating physicians. Eighty-seven percent reported that they diagnosed a new mental problem, and 93% said that the modules clarified suspected symptoms. However, 26% thought the procedure was too time consuming, and 80% believed that reimbursement would be necessary for routine use. Detection of cases using the diagnostic modules was associated with physician intervention and with independent assessment of patient impairment. Over three quarters of the patients (76.4%) who were classified as positive by the physician interview for any of the diagnoses also tested positive on the SCID-P. Two thirds of the patients (62.7%) with at least one of the disorders (according to SCID-P) were classified by the physician interview as having a mental disorder. However, the operating characteristics varied across specific disorders and indicated a need for revisions and testing in larger samples. CONCLUSIONS: These brief physician-administered diagnostic interview modules are part of a screening and diagnostic system (Symptom-Driven Diagnostic System for Primary Care [SDDS-PC], The UpJohn Co, Kalamazoo, Mich) to detect mental disorders in primary care patients. The pilot results help establish their feasibility and validity.

Adult↗