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PubMed2003

The Confederate medical laboratories.

During the Civil War, the scarcity and expense of imported drugs forced the Confederate Army to establish several medical laboratories to manufacture drugs for military use. The laboratories produced medicines from indigenous plants and also made non-plant-based drugs. The Confederate Surgeon General and the Chief Purveyor in Richmond, VA, coordinated activities of most of the laboratories. The laboratories employed talented and resourceful personnel and manufactured a large volume and wide variety of drugs, the most useful of which included ether, chloroform, and opiates. The pharmaceutical quality of the laboratories' output was evidently uneven. Empirical testing in military hospitals helped determine the clinical value of indigenous remedies. The Confederate medical laboratories participated in a coordinated effort to supply the Army with substitutes for drugs whose availability was curtailed or uncertain.

Drug Compounding↗
PubMed1998

A study of laboratory based faecal occult blood testing in Melbourne, Australia. The Faecal Occult Blood Testing Study Group.

Faecal occult blood tests (FOBT) are widely used in clinical practice and are under increasing scrutiny as a tool for colorectal cancer screening. However, there is little information regarding the quality of testing performed in pathology laboratories. Therefore, we asked 13 pathology laboratories in Melbourne, Australia, to test coded contrived faecal samples prepared from a composite stool specimen which had been spiked to various concentrations of haemoglobin. The samples were provided to the laboratories in two forms: (i) on/in the sample collection device appropriate for the faecal occult blood test they normally used; and (ii) as a moist faecal sample. Some variation in threshold analytical sensitivity between laboratories for the same FOBT was observed for Hemoccult SENSA, ColoRectal, Hematest, MonoHaem and Hemolex suggesting that, at least for those tests, technician training could be improved. Two tests, Hematest and an in-house FOBT did not perform as well as the other FOBT. When samples were sent in moist form, Hemoccult SENSA (P = 0.0002), ColoRectal (P = 0.02) and MonoHaem (P = 0.04) had significantly lower overall positivity rates; for Hemolex the decrease was not significant (P = 0.3). The lower positivity rate with moist samples is important, given that 11 of the 13 laboratories in the study stated that they receive at least some samples in moist form. Thus, technician training and laboratory procedure need to be reviewed to maximize the benefits of faecal occult blood testing in clinical practice, especially with its expanding role in colorectal cancer screening.

Australia↗
PubMed1988

Extra-laboratory blood glucose measurement: a policy statement.

The introduction of test strips for measurement of blood glucose has led to their widespread use by medical and paramedical staff outside the central laboratory. While many users have developed ad hoc schemes of training and quality control, formal guidelines have not been presented. This paper makes recommendations on various aspects of extra-laboratory blood glucose measurement in hospitals, but not in the home, with the aim of improving the safety and reliability of results. It is recommended that: 1. a formal programme of training should be devised by staff in the laboratory together with those in the diabetes service and others as appropriate; 2. laboratory and diabetes staff should train, assess, and approve more senior users who would then take responsibility for the training and performance of more junior colleagues; 3. all users should demonstrate their competence at regular intervals; 4. there should be a quality assurance programme arranged by the laboratory which tests the performance of the operator and the equipment; 5. laboratory staff, in consultation with users, should be responsible for the selection and purchase of equipment; 6. equipment should be cleaned and maintained on a regular basis by users.

Allied Health Personnel↗
PubMed2005

Clandestine drug laboratories in Australia and the potential for harm.

The emphasis in the literature regarding illicit drugs has been overwhelmingly on the subject of harm caused by their ingestion. Little has been reported on the potential and real harm associated with the illicit manufacture of drugs. This paper describes the increasing prevalence of clandestine drug laboratories in Australia, overwhelmingly devoted to the manufacture of methamphetamine. The nature of the illicit synthetic process is reviewed together with its inherent dangers for the 'cook', first responders and bystanders including children, and the environment. We have analysed the emerging trends in manufacture and seizure in Australia, and offer suggestions to remedy significant deficiencies in knowledge and policy in the management of clandestine drug laboratories, especially with reference to clinical management issues, data collection, environmental contaminants and remediation, legislation and research. In particular, we conclude that: The problem of clandestine drug laboratories is growing in Australia, reflecting patterns world-wide. There are significant health and environmental implications of this growth. First responders should ensure that specialised expertise is available when decommissioning detected laboratories. Clinicians should familiarise themselves with the types of injuries associated with clandestine drug manufacture. Legislatures without a clandestine drug laboratory registry should establish one. Where it doesn't exist, legislation should be sought to curb the spread of this unwanted phenomenon. Significant opportunities exist for further research into the harm caused to first responders, the community, and the environment by clandestine laboratories.

Australia↗
PubMed1997

The dental student as technician: an 18-year follow-up of preclinical laboratory programs.

In 1977, a survey of American and Canadian dental schools was conducted by Weintraub to determine the delegation of laboratory procedures in preclinical and clinical complete and removable partial denture programs. This was performed in light of challenges raised to the value of requiring dental students, rather than laboratory technicians, to perform the various laboratory procedures involved in the fabrication of complete and removable partial dentures. Since 1977, the rate of edentulism has declined in the United States, and fewer edentulous patients have sought regular dental care. In addition, approximately 20% fewer curriculum hours have been spent in dental schools in removable prosthodontic instruction; a declining number of graduating dental students have felt comfortable with their level of knowledge of removable prosthodontics, especially complete dentures, and have performed fewer removable prosthodontic procedures in practice because of a perceived lack of treatment cost-effectiveness. The present study, an 18-year follow-up to the 1977 survey, was designed to determine if such trends toward a deemphasis on removable prosthodontic treatment have affected the mechanisms of instruction in and the extent to which dental schools instruct students about removable prosthodontics laboratory procedures. The 1995 survey was mailed to 53 American dental schools. Forty-six schools returned the completed survey, for a response rate of 87%. Results showed that the proportion of schools with removable prosthodontic preclinical programs, especially those in removable partial dentures, increased, as did the relative amount of material presented to students in these programs. This was accomplished primarily through the enhancement of laboratory technician support, both in-house and commercial, of student preclinical removable prosthodontic laboratory procedures. The conflict between these outcomes and the call by the dental community, as well as that of the 1995 Institute of Medicine Study, for a reduced emphasis on teaching students about the technical details involved in removable prosthesis fabrication is recognized and explored.

Curriculum↗
PubMed1997

The dental student as technician: an 18-year follow-up of clinical laboratory programs.

In 1977, a survey of American and Canadian dental schools was conducted by Weintraub to determine the delegation of laboratory procedures in preclinical and clinical complete and removable partial denture programs. This was performed in light of challenges raised to the value of requiring dental students, rather than laboratory technicians, to perform the various laboratory procedures involved in the fabrication of complete and removable partial dentures. Since 1977, the rate of edentulism has declined in the United States, and fewer edentulous patients have sought regular dental care. In addition, approximately 20% fewer curriculum hours have been spent in dental schools in removable prosthodontic instruction; a declining number of graduating dental students have felt comfortable with their level of knowledge of removable prosthodontics, especially complete dentures, and have performed fewer removable prosthodontic procedures in practice because of a perceived lack of treatment cost-effectiveness. The present study, an 18-year follow-up to the 1977 survey, was designed to determine if such trends toward a de-emphasis on removable prosthodontic treatment have affected the mechanisms of instruction in and the extent to which dental schools instruct students about removable-prosthodontics laboratory procedures. The 1995 survey was mailed to 53 American dental schools. Forty-six schools returned the completed survey, for a response rate of 87%. Results showed that the relative amount of material presented to students in clinical removable prosthodontics programs increased, primarily through the enhancement of laboratory technician support, both in-house and commercial, of student clinical removable prosthodontic laboratory procedures. The increase was greater than in preclinical removable prosthodontic programs, which were described in a companion article. The conflict between these outcomes and the call by the dental community, as well as that of the 1995 Institute of Medicine Study, for a reduced emphasis on teaching students about the technical details involved in removable prosthesis fabrication is recognized and explored.

Canada↗
PubMed2006

Multiple-laboratory comparison of in vitro assays utilized to characterize hematopoietic cells in cord blood.

BACKGROUND: Understanding the variability in results obtained by multiple laboratories is important because cord blood units are distributed worldwide for transplantation. STUDY DESIGN AND METHODS: Four exercises were conducted by multiple laboratories to assess assay variability on nucleated cell (NC), mononuclear cell (MNC) by hematology analyzers [HAs], and CD34+ cell (flow cytometry) measurements. Exercise 1 was an intralaboratory exercise in which the reproducibility of cell measurements was determined. Exercises 2 and 3 involved the shipment of identical processed cord blood samples. In Exercise 2, laboratory-specific methods were utilized. In Exercise 3, two commercial CD34+ cell methods (Stem-Kit and TruCOUNT) were used. In Exercise 4, CD34+ cell levels were determined on repetitive regating of identical list-mode files. RESULTS: Intralaboratory reproducibility was highest for NC measurements and lowest for CD34+ cell measurements. In Exercise 2, all laboratories except one utilized HA with an impedance technology and determined comparable results for NC and MNC levels, whereas the other laboratory utilized a HA with an optical counting method. Substantial variation was observed on measuring CD34+ cells with ranges of 32 to 141, 32 to 66, and 25 to 116 CD34+ cells per microL for the three identical samples. In Exercise 3, on the use of one specific commercial assay, the ranges of CD34+ levels were 214 to 411 and 62 to 178 cells per microL for the two identical samples. Nearly all participating laboratories determined comparable CD34+ levels on the use of identical list-mode files. CONCLUSION: These studies indicate that substantial variability in CD34+ cell levels were determined with flow cytometry. The variability in NC and MNC levels was minimal with HA methodology.

Antigens, CD↗
PubMedDate not supplied

Evaluation of an emergency-procedure teaching laboratory for the development of proficiency in tube thoracostomy.

OBJECTIVE: Emergency-procedure laboratories are not a standardized part of the curriculum for emergency medicine residency programs. The authors evaluated the efficacy of an emergency-procedure laboratory to teach medical students and residents the performance of tube thoracostomy. METHODS: A prospective repeated-measures study of tube thoracostomy placement training was performed in an animal-laboratory setting. Participants were six first-postgraduate-year emergency medicine residents and six fourth-year medical students. Each participant was given a written pretest on tube thoracostomies followed by lectures on tube thoracostomy, venous cutdown, peritoneal lavage, and surgical airway. The procedure laboratory, using an anesthetized canine model (20-25 kg), was then conducted. Tube thoracostomies were timed from skin incision to passage of the tube into the thoracic cavity with subsequent tube fogging. Four attempts per participant were documented. Eighteen days later, an identical procedure laboratory was conducted for the same students including a written posttest identical to the pretest. RESULTS: The written test scores improved for every participant (p < 0.0001). Mean times for procedures completion improved from 121 sec to 39 sec (p = 0<.001) during the first session and improved from 58 sec to 28 sec (p = 0.005) during the second session. Retention of skills was indicated by significant shortening of the time to completion from the first attempt of the first session to that of the second session (121 sec to 58 sec, p = 0.002). CONCLUSION: This procedure laboratory, which emphasized skill repetition, led to improvement in procedural speed and retention of tube thoracostomy skills over time. This approach to teaching clinical procedures should be considered for emergency medicine residency programs and for continuing medical education courses that emphasize acquisition of clinical procedural skills.

Animals↗
PubMed2006

Wide variability in laboratory reference values for serum testosterone.

INTRODUCTION: The laboratory determination of testosterone levels consistent with a diagnosis of hypogonadism is complicated by the availability of multiple testosterone assays and varying reference ranges. AIM: To assess current laboratory practices regarding availability of testosterone assays and use of reference values. METHODS: A telephone survey of 12 academic, 12 community medical laboratories, and one national laboratory. MAIN OUTCOME MEASURES: Types of androgen assays offered and determination of reference values. RESULTS: All of the academic and eight of the community centers performed total testosterone testing. Free testosterone was performed in-house by six of the 12 academic and one community center. Testing for bioavailable testosterone, free androgen index, and percent free testosterone was performed in-house by no more than two centers. There were eight and four different assays used for total and free testosterone, respectively. One national laboratory offered equilibrium dialysis measurement of free testosterone. Of the 25 labs, there were 17 and 13 different sets of reference values for total and free testosterone, respectively. The low reference value for total testosterone ranged from 130 to 450 ng/dL (350% difference), and the upper value ranged from 486 to 1,593 ng/dL (325% difference). Age-adjusted reference values were applied in four centers for total testosterone and in seven labs for free testosterone. All reference values were based on a standard statistical model without regard for clinical aspects of hypogonadism. Twenty-three of the 25 lab directors responded that clinically relevant testosterone reference ranges would be preferable to current standards. CONCLUSIONS: Laboratory reference values for testosterone vary widely, and are established without clinical considerations.

Androgens↗
PubMed2000

Development of the antinuclear and anticytoplasmic antibody consensus panel by the Association of Medical Laboratory Immunologists.

The Association of Medical Laboratory Immunologists (AMLI) have developed a panel of antinuclear and anticytoplasmic antibody consensus sera that can be useful for enzyme immunoassay (EIA), Ouchterlony, and immunofluorescence assay methods. It was developed to assist in the evaluation of newly available EIA methods for the detection of autoantibodies. The panel of sera was evaluated in several clinical laboratories and a large number of laboratories owned by manufacturers of clinical autoantibody testing kits. The majority of sera performed well for the EIAs in both the clinical laboratories and the manufacturers' laboratories, but some samples had discrepant results. A major source of discrepancy is the current inability of the EIA results to be directly compared in a quantitative way as no standardization exists. The evaluation demonstrated lower sensitivity of detection by the Ouchterlony method. The limited evaluation of the sera with immunoblotting and Western blotting did not show good agreement with other methods. Further work must be done to standardize blotting methods prior to their use in routine clinical testing. The sera are now available to vendors and clinical laboratories for use in the detection of SS-A, SS-B, Sm, U1-RNP, Scl-70, Jo-1, double-stranded DNA, and centromere antibodies. The availability of the consensus sera will help evaluate and improve the EIA methods currently being used.

Antibodies, Antinuclear↗
PubMed1995

Laboratory-associated infections and biosafety.

An estimated 500,000 laboratory workers in the United States are at risk of exposure to infectious agents that cause disease ranging from inapparent to life-threatening infections, but the precise risk to a given worker unknown. The emergence of human immunodeficiency virus and hantavirus, the continuing problem of hepatitis B virus, and the reemergence of Mycobacterium tuberculosis have renewed interest in biosafety for the employees of laboratories and health care facilities. This review examines the history, the causes, and the methods for prevention of laboratory-associated infections. The initial step in a biosafety program is the assessment of risk to the employee. Risk assessment guidelines include the pathogenicity of the infectious agent, the method of transmission, worker-related risk factors, the source and route of infection, and the design of the laboratory facility. Strategies for the prevention and management of laboratory-associated infections are based on the containment of the infectious agent by physical separation from the laboratory worker and the environment, employee education about the occupational risks, and availability of an employee health program. Adherence to the biosafety guidelines mandated or proposed by various governmental and accrediting agencies reduces the risk of an occupational exposure to infectious agents handled in the workplace.

Containment of Biohazards↗
PubMed1981

Fatal salmonellosis originating in a clinical microbiology laboratory.

Laboratory-acquired infections concern all microbiologists. During ongoing surveillance of laboratory-acquired enteric infections, salmonella infections in the wife and son of a laboratory worker were documented; the first case was fatal. Neither patient had had any contact with the laboratory. The infecting organisms were Salmonella typhi and a multiply resistant strain of Salmonella agona that were being worked within the laboratory; both strains had been received 1 to 2 years previously for proficiency testing exercises. This report documents the transmission of enteric pathogens beyond the confines of the laboratory, with its tragic outcome, and suggests measures to prevent the recurrence of this problem.

Adolescent↗
PubMed1993

Establishment of a quality assurance program for human immunodeficiency virus type 1 DNA polymerase chain reaction assays by the AIDS Clinical Trials Group. ACTG PCR Working Group, and the ACTG PCR Virology Laboratories.

An independent quality assurance program has been established by the Virology Committee of the AIDS Clinical Trials Group in the Division of AIDS, National Institute of Allergy and Infectious Diseases, for monitoring polymerase chain reaction (PCR) assays for human immunodeficiency virus type 1 (HIV-1) DNA that are performed by 11 laboratories participating in multicenter clinical trials in the United States. To perform HIV-1 DNA PCR for patients in AIDS Clinical Trials Group protocols, each laboratory was initially certified by correctly testing a coded certification panel consisting of eight well-defined clinical whole-blood specimens and 30 cell pellets containing 0, 2, 5, 10, 20, or 50 8E5/LAV cells per 125,000 uninfected peripheral blood mononuclear cells. PCR was performed by one of two standardized commercial assays for amplification and nonisotopic detection of HIV-1 proviral DNA. For continuing certification, each laboratory must correctly test eight coded whole-blood samples per quarter and run three or four coded cell pellets and HIV-1 DNA copy standards with every PCR assay in real time. The PCR results for the coded pellets on each run are entered into an encrypted computer file, which immediately assesses the validity of the run. To date, 10 of 11 laboratories have correctly tested all HIV-1-positive and -negative samples in the initial certification panel on their first or second attempt. Subsequently, 9 of these 11 laboratories have continued to maintain their certified status. The use of commercial HIV-1 DNA PCR assays and an external quality assurance program have ensured that results from different laboratories are comparable and that problems with sensitivity and specificity are quickly identified.

Certification↗
PubMed1996

Evaluation of a quality assurance program for quantitation of human immunodeficiency virus type 1 RNA in plasma by the AIDS Clinical Trials Group virology laboratories.

A number of quantitative assays have been developed by using amplification techniques to measure human immunodeficiency virus type 1 RNA in the plasma of infected individuals. The Virology Committee of the AIDS Clinical Trials Group in the Division of AIDS, National Institute of Allergy and Infectious Diseases, has established a quality assurance program (QAP) for quantitative assays of HIV-1 RNA levels in plasma. The primary objective of the QAP was to ascertain that a laboratory could maintain the precision required to have a 90% power to detect a fivefold difference in RNA copy number between two samples in the same batch. To achieve this goal, the QAP required an intra-assay standard deviation of no greater than 0.15 log10 RNA copies per ml. Panels for proficiency testing consisted of coded replicate samples and a common set of standards. To date, 41 laboratories have participated in the program and have used both commercial and in-house assays. We demonstrated that 65% of the laboratories were capable of attaining the necessary level of intra-assay precision. The fitted regressions indicated that the differences among laboratories that used the same kit were generally greater than the differences among population-average regressions for the kits themselves. The use of an external QAP and a common set of standards reduced differences both among laboratories that used the same kit and among laboratories that used different kits. Thus, use of a common set of standards across clinical trial protocols would allow for cross-protocol comparisons.

Clinical Protocols↗
PubMed2003

Harmonization of pulsed-field gel electrophoresis protocols for epidemiological typing of strains of methicillin-resistant Staphylococcus aureus: a single approach developed by consensus in 10 European laboratories and its application for tracing the spread of related strains.

Pulsed-fieldgel electrophoresis (PFGE) is the most common genotypic method used in reference and clinical laboratories for typing methicillin-resistant Staphylococcus aureus (MRSA). Many different protocols have been developed in laboratories that have extensive experience with the technique and have established national databases. However, the comparabilities of the different European PFGE protocols for MRSA and of the various national MRSA clones themselves had not been addressed until now. This multinational European Union (EU) project has established for the first time a European database of representative epidemic MRSA (EMRSA) strains and has compared them by using a new "harmonized" PFGE protocol developed by a consensus approach that has demonstrated sufficient reproducibility to allow the successful comparison of pulsed-field gels between laboratories and the tracking of strains around the EU. In-house protocols from 10 laboratories in eight European countries were compared by each center with a "gold standard" or initial harmonized protocol in which many of the parameters had been standardized. The group found that it was not important to standardize some elements of the protocol, such as the type of agarose, DNA block preparation, and plug digestion. Other elements were shown to be critical, namely, a standard gel volume and concentration of agarose, the DNA concentration in the plug, the ionic strength and volume of running buffer used, the running temperature, the voltage, and the switching times of electrophoresis. A new harmonized protocol was agreed on, further modified in a pilot study in two laboratories, and finally tested by all others. Seven laboratories' gels were found to be of sufficiently good quality to allow comparison of the strains by using a computer software program, while two gels could not be analyzed because of inadequate destaining and DNA overloading. Good-quality gels and inclusion of an internal quality control strain are essential before attempting intercenter PFGE comparisons. A number of clonally related strains have been shown to be present in multiple countries throughout Europe. The well-known Iberian clone has been demonstrated in Belgium, Finland, France, Germany, and Spain (and from the wider HARMONY collection in Portugal, Slovenia, and Sweden). Strains from the United Kingdom (EMRSA-15 and -16) have been identified in several othercountries, and other clonally related strains have also been identified. This highlights the need for closer international collaboration to monitor the spread of current epidemic strains as well as the emergence of new ones.

Bacterial Typing Techniques↗
PubMedDate not supplied

How promptly are inpatients treated for critical laboratory results?

OBJECTIVE: The purpose of the study is to determine how frequently critical laboratory results (CLRs) occur and how rapidly they are acted upon. A CLR was defined as a result that met either the critical reporting criteria used by the laboratory at Brigham and Women's Hospital or other, more complex criteria. DESIGN: This is a retrospective cohort study in a large academic tertiary-care hospital. MEASUREMENTS: The proportion of chemistry and hematology results obtained in a 13-day period that met the hospital laboratory's critical reporting criteria were calculated. The charts of a stratified random sample of patients with CLRs due to sodium, potassium, and glucose were reviewed to determine the time interval until an appropriate treatment was ordered and the time interval until the critical condition was resolved. RESULTS: In 13 days, 1938 of 201,037 laboratory results (0.96%, or 0.44 per patient-day) met the hospital's critical reporting criteria. In the chart review, 222 CLRs were included in the stratified random sample, and 99 of these met the inclusion criteria. Among these 99 CLRs, the median time interval until an appropriate treatment was ordered was 2.5 hours. This interval was 1.8 hours when the CLR met the laboratory's criteria and a phone call was made, and 2.8 hours when the CLR met more complex criteria not requiring a phone call (p = 0.07). For 27 (27%) of the CLRs, an appropriate treatment was ordered only after five or more hours. The median time until the condition resolved was 14.3 hours: 12.0 hours for CLRs that met the hospital's criteria and 20.9 hours for the CLRs that met the more complex criteria (p = 0.006). CONCLUSION: Although CLRs meeting the hospital's criteria were reported promptly by the laboratory, treatment delays were still common. Results that did not meet the hospital's critical criteria but still represented serious clinical situations were more often associated with treatment delays. Difficulty communicating critical results directly to the responsible caregiver is the likely cause of some delays in treatment. New communications methods, including computer-based technologies, should be explored and tested for their potential to reduce treatment delays and improve clinical care.

Academic Medical Centers↗
PubMed1995

Serological testing in a microbiology laboratory of specimens from patients with suspected infectious disease.

AIMS: To determine how the microbiology laboratories of one region process serological requests from patients with suspected infectious illness, referred to as "clinical syndrome" type patients in this study; to consider areas where improvement in the associated serology service could be made. METHODS: A prospective two month collection of data on all serological requests from patients with suspected infectious illness was undertaken. A questionnaire on laboratory policies/procedures was also completed by the 10 departments taking part. RESULTS: Serology specimens from "clinical syndrome" patients accounted for 1-2% of total microbiology samples. There was significant variation in some of the policies/procedures carried out by the 10 laboratories when handling serological requests. Differences were seen in the use of laboratory protocols for test processing, range of tests performed, demand for second (convalescent) serum samples, storage of serum samples, and reporting of results. CONCLUSIONS: The laboratory management of "clinical syndrome" type requests is complex. Individual pathology departments vary in the way they handle serology specimens but this study highlighted areas which may contribute to improving the appropriateness of testing and the more efficient use of serology resources. These include improving (1) clinician education, (2) pathology request forms to encourage better clinical information, (3) appropriate laboratory protocols to aid decision making on test selection, (4) percentage of convalescent serum samples received together with longer serum sample storage, and (5) turnaround times of serology reports.

Clinical Protocols↗
PubMed1984

Spontaneous abortions among laboratory workers; a follow up study.

An investigation was conducted among all female laboratory workers in the county of Funen to test the hypothesis that work in laboratories during pregnancy increases the risk of spontaneous abortion. Laboratory workers from hospital, university, and other public laboratories and from laboratories in industry were investigated. A socially comparable reference group less exposed to chemicals at work included office workers, technical assistants and designers, physiotherapists, and occupational therapists. Information was obtained through a postal questionnaire study in May 1980 and from hospital records. Neither the occupation in any single category of laboratory nor the alleged exposure to any single chemical during pregnancy showed a significant increase in the odds ratio for spontaneous abortion. A selection bias was found among the non-respondents with respect to both occupation and outcome of pregnancy, but the influence on the results was slight, owing to the small number of non-respondents. The higher rates of hospital admission for spontaneous abortion among the cases compared with the controls indicates that register data are not more valid than self reported data. This leads to several methodological problems that ought to be studied in further detail.

Abortion, Spontaneous↗