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PubMed1992

Laboratory diagnosis of fetal infections.

In utero infections of the fetus can lead to significant morbidity and mortality in the newborn child. The signs and symptoms of clinical disease, however, do not always suggest a given pathogen. The laboratory must be able to provide an early and accurate diagnosis of the causative agent so that prompt and appropriate antimicrobial therapy and medical care can be initiated. The scope of this article includes the methods employed by the laboratory to assist in the diagnosis of bacterial, fungal, parasitic, and viral infections of the fetus. Where appropriate, detection methods were addressed for the diagnosis of the major pathogens responsible for infection during the birth process.

Bacterial Infections↗
PubMed1990

Electroencephalography laboratory diagnosis of prolonged QT interval.

Patients with prolongation of the QT interval are at risk for significant neurological morbidity and mortality secondary to ventricular tachyarrhythmias. These patients frequently undergo electroencephalographic (EEG) examination to evaluate episodes of loss of consciousness, which may be associated with convulsions. Electrocardiogram recording as a part of the EEG is a simple and common practice, but analysis for possible QT prolongation is not routinely performed by electroencephalographers. This is, in part, due to the fact that while calculation of the corrected QT interval is straight forward, a calculator is generally required. A nomogram that is presented simplifies determination of the corrected QT interval, facilitating diagnosis of prolongation of the QT interval in the EEG laboratory.

Adult↗
PubMed1990

Laboratory diagnosis of acute toxoplasmosis by immunosorbent agglutination assay (IgM ISA).

A group of 401 patients suspected for toxoplasmosis was examined by the indirect immunofluorescent antibody test (IFAT). All patients positive in IFAT (176) were examined by the immunosorbent agglutination assay (IgM ISA). In the IgM ISA 154 of them were negative, 10 temporarily and 12 high-positive. Some of high-positive patients were examined repeatedly; decrease of high levels of specific IgM antibodies occurred 2-9 months after the first examination. For the IgM ISA antigen prepared from peritoneal exudate of experimentally infected mice was used. The antigen was stable at 4 degrees C or in liquid nitrogen at least 1 year. The IgM ISA combined with IFAT and IgM IFAT was proved satisfactory for the diagnosis of acquired acute toxoplasmosis and can be recommended for laboratories with lower capacity.

Acute Disease↗
PubMed1979

Laboratory diagnosis of postoperative sepsis of the musculoskeletal system.

The diagnosis of acute sepsis after musculoskeletal surgery is based on the results of the clinical examination. Microbiologic evaluation of clinical specimens permits identification of the causal organism(s) and of the susceptibility studies. In the subacute stage of postoperative sepsis, roentgenographic examination, a peripheral leukocyte count, erythrocyte sedimentation rate, hemoglobin level, and nuclear scans can be helpful to the clinician. Frozen section histologic examination of tissues and Gram staining of fluids obtained at surgery have resolved the choice in differential diagnosis between aseptic and septic loosening of painful prosthetic components. Laboratory evaluation, including tissue biopsy, identifies the chronic complications of amyloidosis and malignant change in patients with long term sepsis of the musculoskeletal system.

Arthritis, Infectious↗
PubMed1999

A national audit of the laboratory diagnosis of tuberculosis and other mycobacterial diseases within the United Kingdom.

In order to audit United Kingdom laboratory diagnostic and reference services including novel molecular methods for tuberculosis, a questionnaire was sent to laboratories submitting specimens to the PHLS Mycobacterium Reference Unit (MRU) and regional centres and to the Scottish Mycobacteria Reference Laboratory (SMRL) in 1996-7. Nationally, 67.2% of laboratories responded. Most UK laboratories were fully or conditionally CPA accredited and take part in the NEQAS proficiency scheme. On average only 3.3% of primary samples submitted for mycobacterial diagnosis in 1995 produced a mycobacterial culture from approximately half as many patients (that is, a mean of 1488 specimens producing 49 isolates from 23 patients). Potentially over 380,000 specimens are processed for mycobacteria in the UK each year. The majority of laboratories use 4% NaOH +/- NALC for specimen decontamination. Culture on solid media was used by most laboratories and 62.9% also use liquid media. Most laboratories incubated cultures for eight weeks. Few laboratories use molecular diagnostic methods. Laboratories were most likely to use molecular methods for diagnosing tuberculous meningitis and for specimens from immunocompromised patients, although usage was strongly influenced by cost. Within England and Wales 43.9% (47/107) and 56% (61/109) of laboratories wanted a rapid service for rifampicin resistance detection in M tuberculosis from immunocompetent and immunocompromised patients, respectively. In regard to a tuberculous meningitis service, 80.5% (43/112) and 84.3% (102/121) of laboratories wanted this service for immunocompetent and immunocompromised patients, respectively. The quality of reference services was rated as "very good"/"good" by 85.6% of respondents nationally. Rapid molecular amplification diagnostic services were established at the PHLS MRU for rifampicin drug resistance detection nationally and for tuberculous meningitis at the MRU.

Bacteriological Techniques↗
PubMed1987

Laboratory diagnosis of herpesvirus infections.

The diagnosis of infection due to herpesviruses can be performed by several laboratory techniques, including virus culture, demonstration of virus-specific cellular antigens, detection of virus-induced serum antibodies, detection of viral nucleic acids (using radiolabeled probes), or visualization of histologic changes in infected tissue. Virus culture is the most sensitive technique for diagnosis of most infections due to herpes simplex virus (HSV) and cytomegalovirus (CMV), but is insensitive for the diagnosis of varicella-zoster (VZV) infection and not routinely available for Epstein-Barr virus (EBV). Identification of viral antigens on infected cells with monoclonal antibodies is useful for definitive identification of virus in cell culture and for rapid diagnosis of infection due to HSV, VZV, or CMV. Serologic studies are useful for the diagnosis of EBV infection, because clinical symptoms and an antibody response occur simultaneously, and other diagnostic tests are generally unavailable. Although serologic studies may be used retrospectively to diagnose infections due to HSV, VZV, or CMV, these results are seldom available in time to be useful in managing the acute infection or in guiding antiviral chemotherapy. Newer diagnostic techniques, such as detection of viral nucleic acids using radiolabeled probes, may become useful in the future for the rapid diagnosis of EBV or CMV infection.

Antibodies, Viral↗
PubMed2004

Laboratory diagnosis of canine GM2-gangliosidosis using blood and cerebrospinal fluid.

In the present study, laboratory techniques were used to diagnose canine GM2-gangliosidosis using blood and cerebrospinal fluid (CSF) that can be collected noninvasively from living individuals. Lysosomal acid beta-hexosaminidase (Hex) was measured spectrofluorometrically using 4-methylumbelliferyl N-acetyl-beta-D-glucosaminide and 4-methylumbelliferyl 7-(6-sulfo-2-acetamido-2-deoxy-beta-D-glucopyranoside) as substrates. Main isoenzymes A and B of Hex in leukocytes were also analyzed using cellulose acetate membrane electrophoresis. GM2-ganglioside in CSF was detected and determined quantitatively by using thin-layer chromatography/enzyme-immunostaining method with anti-GM2-ganglioside antibody. In normal dogs, Hex activities could be determined in leukocytes, serum, and CSF and the total activities were markedly reduced in all the enzyme sources in a dog with Sandhoff disease. Electrophoresis of a leukocyte lysate from a normal dog showed that the Hex A and Hex B were not separated distinctively with formation of a broad band, whereas there were no bands in electrophoresis of a lysate from a dog with Sandhoff disease, showing a deficiency in the total enzyme activity. GM2-ganglioside could be detected and determined quantitatively in as little as 100 microl of canine CSE GM2-ganglioside in CSF in a dog with Sandhoff disease increased to 46 times the normal level. In conclusion, the methods in the present study are useful for diagnosis of canine GM2-gangliosidosis. These techniques enable definitive and early diagnosis of canine GM2-gangliosidosis even if tissues and organs cannot be obtained.

Animals↗
PubMed1994

Use of an insertion sequence for laboratory diagnosis and epidemiologic studies of tuberculosis.

A dramatic improvement in the rapidity and accuracy of laboratory testing for tuberculosis is anticipated in the near future from the application of molecular biology techniques. The polymerase chain reaction and other nucleic acid amplification methodologies have the potential to detect, amplify, and identify very small quantities of Mycobacterium tuberculosis DNA directly in a clinical specimen, even on the same day it is collected. Within the past 3 years, a number of polymerase chain reaction-based assays for tuberculosis have emerged. The development and evaluations of the polymerase chain reaction assay based on the insertion sequence IS6110 are described. For practical application in the clinical setting, amplification assays require a simple, reliable sample preparation method; an internal positive control to monitor for inhibitors; a method for eliminating contamination with amplicon (a polymerase chain reaction product) to prevent false-positive results; and a simple, sensitive detection method. The DNA fingerprinting method that uses IS6110 probes provides a means of differentiating individual strains of M tuberculosis and is a powerful tool for epidemiologic studies. The method and its applications are described.

DNA Fingerprinting↗
PubMed1975

Laboratory diagnosis of rheumatoid arthritis. Prospective study of 85 patients.

Because early diagnosis of rheumatoid arthritis is difficult increasingly important, we have assessed the value of laboratory investigation in 85 patients with knee effusions studied from presentation and followed for sufficiently long periods to allow a definite diagnosis. Histopathology on needle biopsy specimens narrowed the differential diagnosis to rheumatoid arthritis and closely related conditions even at an early stage of disease and also allowed recognition of other conditions which would not otherwise have been detected. Immunofluorescence on similar specimens further narrowed differential diagnosis since the presence of IgM was found to be very suggestive of rheumatoid arthritis. Other tests were of less value. It is concluded that laboratory investigation can improve diagnostic sensitivity and specificity in relatively early rheumatoid arthritis.

Adolescent↗
PubMed1991

[Nucleic acid molecular hybridization as a method for the laboratory diagnosis of influenza: its potentials and prospects].

Experiments carried out by the present moment in a number of laboratories indicate that the method of molecular hybridization (MH) has great diagnostic potential. Sufficient methodological mastery of the reaction of radioactively labeled DNA probes with RNA samples applied into a polymer membrane and good supply of commercially available materials make it possible to recommend this method for use in reference laboratories at specialized diagnostic centers. Hybridization should be used in combination with traditional virological and serological tests; the combined use of MH and the enzyme immunoassay for the determination of viral antigens permits the documentation of 90-98% of all cases of influenza A with sufficient rapidity. In the near future DNA probes for the diagnosis of influenza B and C are likely to appear. MH has rather good prospects for the analysis of experimental infection in laboratory animals, as well as for the study of the replication of influenza virus in all cultures. The prospects of the study of the processes of expression of individual genes seem to be particularly attractive. MH may play an important role as a tool for documenting vaccinal reaction, as well as for the study of the action of different chemical preparations in volunteers. And finally, the greatest expectations are linked with the use of MH for the search of inapparent (persistent, latent, etc.) forms of influenza virus infection both in experimental systems and in humans. Optimistic prospects of the studies in this field are based on high sensitivity of this method combined with its equally high specificity. An additional reserve for enhancing sensitivity is also present here due to the amplification of target molecules.

DNA Probes↗
PubMed2001

Laboratory diagnosis of heparin-induced thrombocytopenia type II after clearance of platelet factor 4/heparin complex.

Laboratory confirmation of heparin-induced thrombocytopenia (HIT) is limited by assay sensitivity. We investigated whether laboratory confirmation can be improved after antigen clearance by determining free antibody and combining the results of antigenic and biologic assays. Blood samples were collected over 5 to 6 weeks in 14 HIT patients. As an antigenic assay, the fluorescence-linked immunofiltration assay (FLIFA) was performed, and as a biologic assay, the carbon 14-labeled serotonin release assay was performed. At day 1 when heparin was stopped, 11 of 14 patients showed positive results in both assays; thus each assay had a sensitivity of 80%. The 3 patients with negative results seroconverted in one or both assays during the subsequent 7 days. Combining the positive results of the assays increased the sensitivity to 100% at day 7, regardless of whether the antigenic or the biologic assay was performed first. Both assays became negative in all patients within 5 to 6 weeks. The sensitivity of antigen and biologic assays in HIT patients increased to 100% after the time course of the heparin-induced antibody. We assume that in some HIT patients the free antibody can be detected after withdrawal of heparin and after clearance of the platelet-factor 4/heparin complex.

Aged↗
PubMedDate not supplied

Laboratory diagnosis of iron deficiency in a developing country, Pakistan.

In developing countries, such as Pakistan, laboratories do not routinely screen for iron deficiency unless the patient presents with symptoms of anaemia. Efforts to prevent the often serious consequences of iron depletion are hampered in developing countries by the expense and impracticality of routinely screening patients using bone marrow examination. Assays for serum iron concentrations, total iron-binding capacity or haemoglobin and examinations of blood films, although more practical, cannot detect the earliest stages of iron deficiency. Serum ferritin appears to be a sensitive, early indicator of iron deficiency and can be easily and relatively inexpensively determined using an immunoassay kit. In the present study, serum ferritin levels were determined using immunoassay and compared to blood films, serum iron levels and total iron-binding capacity values in 300 apparently healthy Pakistanis. In the early stages of iron deficiency, serum ferritin appeared to be a sensitive measure of iron depletion.

Adult↗
PubMed1978

Disseminated intravascular coagulation in patients with meningococcal infection: laboratory diagnosis and prognostic factors.

In 36 patients with meningococcal infection a close association between the laboratory evidence of disseminated intravascular coagulation (DIC) and unfavourable prognostic factors was established. Patients with platelet count lessthan 100000/microliter, Normotest lessthan 50% and plasma fibrinogen concentration less than 100 mg/dl had a serious prognosis. No significant differences could be extablished between patients with infection from serogroup A and B meningococci for either laboratory evidence of DIC or prognostic factors.

Adolescent↗
PubMed1985

[The capacity and limits of laboratory diagnosis].

From observations of the daily cooperation between clinic and out-patient department and laboratory, respectively, result several basic and critical considerations. It is tried to analyse the causes of certain developmental tendencies which by the two sides are regarded as disturbing and unfavourable and to draw conclusion for the sake of a reasonable use of the laboratory capacities and a good cooperation between the partners.

Blood Chemical Analysis↗
PubMed1994

Laboratory diagnosis and monitoring in chronic systemic autoimmune diseases.

The testing done in the diagnostic immunology laboratory contributes to the management of patients with systemic autoimmune diseases. In these diseases the interaction between environmental factors and a genetically dysregulated immune system produces a continually variable level of disease activity. Improved techniques now allow the clinical scientist to assess the integrity of a patient's immune system and to ascertain qualitative or quantitative disturbances in its activation and expression. Cellular and humoral immunity may become independently activated or dysfunctional in certain disease processes, although the generation of amplifying proteins may result in the full clinical expression of immunity and autoimmune inflammation. Autoimmune diseases can, in part, be characterized according to the activation pattern of gene expression encoding the amplifying and proinflammatory cytokines. Modern therapy is increasingly aimed at determining ways to influence discrete elements of the immune apparatus; therefore, it is important to identify and characterize the patterns of expression of the immune system mediators serially in chronic autoimmune disease states. Newer diagnostic procedures stemming from observations in basic and clinical research are expanding the useful database on patients, but they must be carefully evaluated to prove their applicability and efficacy. Because blood samples are the best available specimens for testing, one must consider all the possible sampling problems and pitfalls of using results from peripheral blood to judge changes in function of the lymphoid system.

Arthritis, Rheumatoid↗
PubMed2001

Laboratory diagnosis of ehrlichiosis and babesiosis.

Over the past 15-20 years, four notable tick-borne infections have emerged in the US, Lyme disease, human monocytic ehrlichiosis (HME), human granulocytic ehrlichiosis (HGE) and babesiosis (Table). In contrast to the laboratory diagnostic procedures established for Lyme disease, RMSF and tularemia, the laboratory diagnostic procedures for the diagnosis of HME, HGE and babesiosis are not yet standardized and continue to be revised.

Animals↗