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PubMed2001

Commentary: advances in the laboratory diagnosis of celiac disease.

Anti-endomysial autoantibodies are very useful in the diagnosis and monitoring of celiac disease (gluten-sensitive enteropathy) due to their high sensitivity and specificity for that disorder. The recent discovery that the autoantigen responsible for the endomysial pattern is tissue transglutaminase (tTG) has led to the commercial development of automated enzyme immunoassays for quantitation of that autoantibody. These assays are standardized to provide highly accurate and comparable testing between laboratories for anti-tTG autoantibodies. Celiac disease is a common genetic disease in populations of Europe and the United States. It has a spectrum of expression ranging from silent or mild to severe, with resulting malabsorption that produces multiple-organ system effects due to malnutrition. Many cases miss the diagnosis because the symptoms are not classic or the clinical syndrome is not severe. Because the treatment of celiac disease (avoidance of wheat products) is so effective and inexpensive and because celiac disease is so common in selective populations, a highly reliable test for its detection such as anti-tTG should find wide application in clinical practice.

Antibodies↗
PubMed1989

[The use of the potentials of the molecular hybridization of nucleic acids as a method for the laboratory diagnosis of influenza in research on vaccinal infection].

The data obtained as the result of the complex examination of volunteers immunized with live influenza vaccine, type A (H3N2), showed that the determination of the RNA-containing structures by the method of the molecular hybridization of nucleic acids (MHNA) was highly sensitive and reliable. This method proved to be more sensitive than common laboratory diagnostic tests (the isolation of the virus in chick embryos, the analysis of seroconversion, the antibody fluorescence test) and was not inferior to the complex of clinical tests based on the analysis of microsymptoms. The reliability of the positive (according to the data obtained by MHNA) results was very high: not less than 85% of them were confirmed by other tests.

Administration, Intranasal↗
PubMed1989

Comparative field evaluation of the fluorescent-antibody test, virus isolation from tissue culture, and enzyme immunodiagnosis for rapid laboratory diagnosis of rabies.

The rabies tissue culture infection test (RTCIT) and rapid rabies enzyme immunodiagnosis (RREID) were compared to the fluorescent-antibody test (FAT) with field specimens. At the French National Reference Center for Rabies, 15,248 specimens were analyzed by FAT and RTCIT, and 2,290 of those specimens were also tested by RREID; 818 other specimens were tested by FAT and RREID in 12 laboratories located in Africa, Asia, and Latin America. The sensitivities and specificities of RREID and RTCIT were comparable. This study showed that both tests can be used as backup procedures to confirm FAT. RREID is also strongly recommended for epidemiological studies and for laboratories which are not equipped for performing FAT.

Africa↗
PubMed2000

Laboratory diagnosis, epizootiology, and efficacy of marker vaccines in classical swine fever: a review.

Detection of classical swine fever virus (CSFV) can be achieved by a range of assays of which the most commonly used are: immunohistochemical and virus culture techniques. New developments have enabled the detection of viral proteins by enzyme-linked immunosorbent assays (ELISAs) and the detection of the viral genome by RT- PCR. So far, laboratory findings show that the latter assays may supplement or replace the conventional techniques in the near future. The detection of serum antibody against structural and non-structural proteins of CSFV has been improved by developments in recombinant DNA techniques and has lead to a range of ELISAs. Although the characteristics of these ELISAs are excellent, positive results still need to be confirmed in the virus neutralization test. The available amount of sequence data enables diagnosticians to type strains of CSFV as different by comparing several parts of the genome. In some cases, this can provide conclusive evidence if a primary or secondary outbreak has been detected. Increased efforts focused on the retrieval of relevant data on the introduction of CSFV in a pig holding and the spread of CSFV in- and between pig holding(s) has generated more insight into the epizootiology of the disease. A successful control and eradication programme for classical swine fever (CSF) can consist of zoosanitary measures and/or vaccination. The latter can compromise the export of live pigs and pig products considerably unless marker vaccines have been used. Several studies were performed to determine the efficacy of an E2 subunit vaccine and live recombinant vaccine candidates. Firstly, we determined the 95% protective dose of an E2 subunit vaccine at 32 microg E2 per dosage after a single application. Further studies with a single administration of the subunit vaccine showed that: the vaccine was stable for a prolonged period after production, was able to reduce horizontal and vertical transmission of CSFV among vaccinated pigs, and provided protection for at least 6 months. An E(rns) antibody discriminatory assay was developed for use in combination with the subunit vaccine. Evaluation of the E(rns) ELISA showed that the sensitivity of the assay was lower than but that the specificity was equal to that of existing antibody assays. Two live recombinant marker vaccines were evaluated for the induction of clinical protection and reduction of transmission of CSFV shortly after vaccination. Results showed that these vaccines provided good clinical protection 1 week after a single vaccination. Research has shown that marker vaccines can be used in the future to support the control and eradication of CSFV.

Animals↗
PubMed2001

"Second-look" cytotoxicity: an evaluation of culture plus cytotoxin assay of Clostridium difficile isolates in the laboratory diagnosis of CDAD.

Clostridium difficile is one of the most frequent causes of hospital-acquired diarrhoea. Our objective was to prove that some stool samples with a direct negative cytotoxicity assay may indeed harbour toxigenic C. difficile and that this can be demonstrated by performing a "second-look" cytotoxicity assay using the isolated C. difficile strains. Over an eight-year period (1992-1999), the 8241 stool samples submitted for direct cell culture from patients with suspected C. difficile-associated diarrhoea (CDAD) were simultaneously plated on cycloserine cefoxitin fructose agar. C. difficile strains isolated from samples with a negative direct cell culture assay were re-tested for toxin production "second-look" cell culture assay). Using both methods 6423 samples (78%) were negative. Of the remaining 1818 samples, 127 (7%) yielded C. difficile isolates which were confirmed as non-producers of toxin by both methods, 1437 (85%) were positive in direct cell culture assay, and 254 were positive only after the "second-look" cell culture assay. Thus, our approach allowed us to detect an extra 15% of toxin-producing strains that could have gone undetected otherwise.The combination of direct-cell culture assay, culture for toxigenic C. difficile and "second-look" cell culture assay enhances the potential for diagnosis of CDAD and enables us to be more efficient with our patient care resources.

Bacterial Toxins↗
PubMedDate not supplied

[Notes on the laboratory diagnosis of dengue virus].

Some aspects of interests connected with the virological, serological and molecular diagnosis of dengue and its most severe form, dengue hemorrhagic fever, which has turned into the most important arthropod-borne viral disease, are updated.

Antibodies, Viral↗
PubMed1979

Trichomonas vaginalis infections in Sydney: laboratory diagnosis and prevalence.

The prevalence of trichomoniasis in Sydney was determined by examining 1070 sexually active females in three different practices. Infection rates ranged from 17.8% in a sympatomatic venereal-disease clinic group to 0.5% in non-promiscuous family-planning clinic patients. In each of these categories, the infestation rate, when compared with overseas reports, was lower but no explanation for this difference is apparent. Of the various laboratory methods used to detect Trichomonas vaginalis, the most sensitive was a culture method. The most convenient and reliable microscopy technique was phase-contrast microscopy which detected 80% of those with positive culture results. Stuart's Transport Medium will maintain trichomonad's viability for at least 24 hours and allow vaginal specimens to be reliably transported for examination.

Australia↗
PubMed1981

[Laboratory diagnosis of idiopathic myelofibrosis. Review of the literature and presentation of 15 cases].

We report on 15 patients affected by myelofibrosis. The main clinical aspects were hepatosplenomegaly, anemia and leukocytosis. Immature cells and anisopoikilocytosis of the erythrocytes were frequently found in the peripheral blood. At bone biopsy, various aspects of panhyperplasia, increase in the reticular fibers, myeloid fibrosis and osteosclerosis were observed. Leukocyte alkaline phosphatase was frequently elevated. The clinical and laboratory course of the disease, causes of death and the possible etiopathogenetic aspects of this disease are considered and discussed.

Adult↗
PubMed1981

Noninvasive vascular laboratory diagnosis of deep venous thrombosis.

One hundred and seventeen consecutive patients with suspected deep venous thrombosis (DVT) were studied for a total of 233 limbs in a period of two years. Doppler signals were assessed at the femoral, popliteal, and posterior tibial veins. The pulse volume recorder was used to determine segmental venous capacitance and maximum venous outflow. The mean age was 55.2 years and the male to female ratio was 1:1. Of the 113 legs without suggestion of DVT studies as controls, three were found to have DVT by laboratory criteria and resulted in three cases of bilateral DVT. One hundred and ten limbs that were clinically unsuspected and 79 (66%) that were suspected were negative by the laboratory method. Of these, 106 unsuspected limbs and 42 suspected (35%) did not require venography and were not treated. Thirty-seven suspected legs (31%) and four unsuspected were proven to be negative not only by the laboratory criteria, but also by venography. Eighteen (15%) clinically suspected limbs and two (2 per cent) unsuspected limbs were positive both by venography and laboratory criteria. Eighteen (15%) suspected limbs and one unsuspected were positive by laboratory criteria and were treated without venographic confirmation. There was one false-positive and four false-negatives for an overall error of 4.2 per cent. From the true accuracy rate of 92 per cent, sensitivity of 83 per cent, and specificity of 98 per cent, the author concludes that this is a useful method in the diagnosis of DVT. Most of the false-negatives occurred in patients with recurrent DVT.

Adolescent↗
PubMed2004

Improved laboratory diagnosis of bacterial and fungal infections in patients with hematological malignancies using PCR and ribosomal RNA sequence analysis.

During October 1999 to November 2000, 98 blood culture specimens from the same number of febrile episodes originating from 49 patients with hematological malignancies were examined for the presence of eubacteria and fungi based on 16S rRNA gene and the 5.8, 18 and 28S rRNA combined with in vitro PCR amplification and sequencing, in addition to conventional blood culture laboratory techniques. Nineteen of the samples were associated with positive blood cultures. Eubacterial (16S rRNA) PCR detected bacterial DNA in 26 febrile episodes, i.e. in an additional 7 febrile episodes than blood-culture alone. The species identified by partial 16S rRNA gene sequencing were as follows Staphylococcus spp (n = 6), Staphylococcus epidermidis (n = 5), Acinetobacter spp (n = 5), Escherichia coli (n = 2), Enterobacter agglomerans (n = 2), Campylobacter spp (n = 1), Citrobacter spp (n = 1), Corynebacterium spp (n = 1), Enterobacter faecium (n = 1), Ralstonia spp (n = 1), Acidovorax spp. (n = 1) and Stenotrophomonas maltophilia (n = 1). Gram-positive bacteria were found in 12/27 (44.6%) and gram-negative bacteria were found in 15/27 (55.6%). After optimization of a PCR-based fungal detection method, none of the febrile episodes were shown to be attributable to fungi. The results of this study suggest that fungi are not common causal agents of febrile episodes in patients with a hematological malignancy at this centre and that molecular techniques can augment cultural methods in the diagnosis of causal agents of bacteremia in patients, so that appropriate antibiotic regimens may be commenced in patients with culture-negative episodes of infection.

Adolescent↗
PubMed1992

Evaluation of a computer program for teaching laboratory diagnosis of acid-base disorders.

A computer program was evaluated as a tool for increasing the diagnostic acumen of medical housestaff and students in identifying acid-base disorders. The participants were randomized into two groups; group A (N = 20) was encouraged to use the software, and group B (N = 19) was denied access. Pre- and post-tests were administered to delineate the groups' ability to identify correctly an acid-base disorder from laboratory data (electrolytes and arterial blood gas). During 6 weeks, group A used the computer for a mean of 2.83 h (range 1 to 6). The mean +/- SE number of correct answers out of 20 questions, prior to use of the computer program, were 5.7 +/- 0.8 (95% confidence interval 3.9 to 7.5) for group A and 5.2 +/- 0.6 (95% confidence interval 3.9 to 6.5) for group B. These results were not statistically different. Correct responses increased significantly in group A to 10.3 +/- 0.9 (P < 0.0001, 95% confidence interval 8.4 to 12.2) but did not increase significantly in group B. The data suggest that this software program was effective in increasing the diagnostic capabilities of medical housestaff and students for identifying acid-base disorders.

Acid-Base Imbalance↗
PubMed1987

[Microbiologic-immunologic laboratory diagnosis in suspected meningitis/encephalitis].

The diagnosis on the exclusion of infectious diseases of the central nervous system, especially of bacterial infections still is one of the most important issues in clinical microbiology. In bacterial meningitis, where lethal courses as well as severe sequelae are still frequent, there should be a rapid diagnosis not only with microscopy but also with Limulus test and antigen detection tests because a specific therapy should be initiated as soon as possible. But also viral infections caused by varicella or herpes virus are increasingly susceptible to chemotherapy. The indication for the examination of cerebrospinal fluid, the minimal volume for exhaustive laboratory tests and the possibilities of a stepwise diagnostic procedure are given with reference data from literature for the various techniques. In our experience the synopsis of laboratory results and clinical symptoms yielded in 75% of all cases the exclusion of an infectious etiology of the disease. In 17% a bacterial meningitis or the infection of a hydrocephalus shunt could be diagnosed. Viral infections could be proven in 4% either by antibody or by antigen detection. Only in 1% of all patients the clinical symptoms and the laboratory parameters remained unclear.

Antigens, Bacterial↗