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PubMed1982

Reiter haemagglutination test: a screening test for syphilis.

Using an ultrasonicate of the Reiter treponeme as antigen the Reiter haemagglutination test (RHA) was evaluated as a serological test for syphilis. Comparison of the results of the cardiolipin Wassermann reaction, Reiter protein complement-fixation test, the fluorescent treponemal antibody-absorbed (FTA-ABS) test, the Treponema pallidum haemagglutination test (TPHA) (at dilutions of 1/16 and 1/80), and the Venereal Disease Research Laboratory test with those of the RHA showed that the RHA was sensitive (85.8%) and agreed well (85.8%) with the FTA-ABS test result. Simplicity, sensitivity, availability of the antigen, and the very low cost of this test support its use as a first-line screening test for syphilis.

Antibodies, Bacterial↗
PubMed1997

Evaluation of previously patch-tested patients referred to a contact dermatitis clinic.

BACKGROUND: One of the frustrations for clinicians who use patch testing is the patient in whom screening patch tests does not yield a relevant result that improves patient outcome. Is it allergic contact dermatitis? Was an allergen missed? Is the screening allergen relevant after all? OBJECTIVE: The purpose of this study was to look at the subset of patients referred to a contact clinic who had previously undergone patch testing to seek answers to these questions for this population. METHOD: The charts of all 119 physician-referred patients seen in the contact clinic from February through August 1995 were reviewed. Information was gathered about the sites of dermatitis, previous patch testing results, current patch testing results (using the North American Contact Dermatitis Group series and supplemental allergens when indicated), and final diagnosis. RESULTS: Forty-three patients had previously undergone patch testing. Nineteen had been tested with the True Test and 24 with the screening series presumed to be Hermal. The sites of skin involvement were similar to the untested group (approximately 1/3 hands, 1/3 face/exposed sites, and 1/3 other). Eighteen pretested patients(42%) had been reported to have one or more positive patch tests, with the most frequently reported allergens, including neomycin (4), quaternium 15 (3), Balsam of Peru (3), fragrance (2), and formaldehyde (2). On repeat testing, 77% of the previous positives were again positive, and many were thought to be relevant. Nine of the 18 had additional allergens deemed relevant. Twenty-five pretested patients had been negative on initial patch testing. Eighteen of the 25 (72%) had positive allergens on repeat testing, and most were thought to be relevant. There were 17 reactions to screening allergens and 16 reactions to additional allergens or products. Variations noted with initial negative testing included use of systemic corticosteroids, patient self-removal of tests, and single 48-hour readings. Overall, 27 of 43 pretested patients (63%) were found to have relevant additional allergens with contact clinic evaluation. Screening allergens were underrecognized as being relevant by clinicians in practice. CONCLUSIONS: Patients suspected of having an allergic component to their dermatitis should be patch tested with the screening series of allergens. Interpretation of the relevance of the allergens and appropriate avoidance is a challenge. If screening allergen patch testing is negative or believed to be not relevant in a patient with persistent dermatitis, there may be a high yield on further patch test evaluation.

Dermatitis, Allergic Contact↗
PubMedDate not supplied

[Leukocyte migration inhibitory factor and basophil degranulation in drug reactions].

We performed a prospective study in patients with a medical history of adverse reaction to drugs with the purpose of rule out allergy. We included 31 patients who were attended in the Allergy Service. We compared the sensibility and specificity of the test of inhibition factor of leucocytes migration and degranulation basophil against the exposition. After the statistical analysis, we concluded: the laboratory test, we have already mentioned, have little sensibility and specificity so the exposition test in the quickest, useful, and more simple method to determine drugs allergy, but more dangerous.

Adolescent↗
PubMedDate not supplied

Determination of processed animal proteins, including meat and bone meal, in animal feed.

An intercomparison study was conducted to determine the presence of processed animal proteins (PAPs), including meat and bone meal (MBM) from various species, in animal feed. The performances of different methods, such as microscopy, polymerase chain reaction (PCR), immunoassays, and a protocol based on iquid chromatography (LC), were compared. Laboratories were asked to analyze for PAPs from all terrestrial animals and fish (total PAPs); mammalian PAPs; ruminant PAPs; and porcine PAPs. They were free to use their method of choice. In addition, laboratories using microscopy were asked to determine the presence of PAPs from terrestrial animals, which is applicable only to microscopy. For total PAPs microscopy, LC and some immunoassays showed sufficient results at a concentration as low as 0.1% MBM in the feed. In contrast, PCR was not fit for purpose. In differentiating between MBM from terrestrial animals and fishmeal, microscopy detected 0.5% of terrestrial MBM in feed in the presence of 5% fishmeal, but was less successful when the concentration of MBM from terrestrial animals was 0.1%. The animal-specific determination of MBM from mammals or, more specifically from either ruminants or pigs, by PCR showed poor results, as indicated by a high number of false-positive and false-negative results. The only PCR method that scored quite well was applied by a member of the organizer team of the study. Immunoassays scored much better than PCR, showing sufficient sensitivity but some deficiency in terms of specificity. The results also demonstrated that the reliable determination of MBM from ruminants has not been resolved, especially for low concentrations of MBM (0.1%) in feed. Comparison of the results for mammalian MBM from all methods indicated that, for control purposes, the immunoassay method, especially when applied as dipsticks, could be used as a rapid screening method combined with microscopy to confirm the positive samples. However, implementation of such a system would require that the immunoassays were previously validated to demonstrate that this approach is fit for purpose. The determination of ruminant or porcine PAPs by immunoassays was more difficult, partly because the MBM in this study contained about 50% bovine and porcine material, thereby reducing the target concentration level to 0.05%.

Animal Feed↗
PubMed1994

Comparison of flow cytometric measurement of seminal antisperm antibodies with the mixed antiglobulin reaction and the serum tray agglutination test.

OBJECTIVE: To compare the mixed antiglobulin reaction (MAR) and the serum tray agglutination test (TAT) with the flow cytometric (FCM) measurement of sperm antibodies. To evaluate by FCM the correlation in sperm antibody parameters between paired semen ejaculates obtained 2 to 4 weeks apart and the effect of washing on sperm antibody levels. SETTING: University-based infertility clinic. PATIENTS: The TAT and FCM were done on 81 patients with a positive immunoglobulin (Ig)G-MAR test. The correlation of sperm antibody parameters between paired semen samples was done in 16 men. A few samples were used to study the effect of washing on sperm antibody parameters. MAIN OUTCOME MEASURES: The proportion of spermatozoa positive for IgG and IgA antibodies as well as the number of antibody molecules per spermatozoa measured by FCM. RESULTS: In general, the degree of MAR positivity but not that of the TAT correlated with the sperm antibody load. With reference to FCM the MAR test had an 1% false positive rate, whereas the serum TAT had a 25% false negative rate. Correlation between FCM measurements of paired semen samples was good. Washing the spermatozoa once removed the loosely bound antibodies; further washes were not useful. CONCLUSION: Flow cytometry is a reliable technique that correlates with the MAR test. In patients with a strongly positive MAR, FCM is useful to identify patients with a low sperm antibody load. It is speculated that patients with a low sperm antibody load may respond better to IVF treatment.

Agglutination Tests↗
PubMed2004

SNP discovery in pooled samples with mismatch repair detection.

A targeted discovery effort is required to identify low frequency single nucleotide polymorphisms (SNPs) in human coding and regulatory regions. We here describe combining mismatch repair detection (MRD) with dideoxy terminator sequencing to detect SNPs in pooled DNA samples. MRD enriches for variant alleles in the pooled sample, and sequencing determines the nature of the variants. By using a genomic DNA pool as a template, approximately 100 fragments were amplified and subsequently combined and subjected en masse to the MRD procedure. The variant-enriched pool from this one MRD reaction is enriched for the population variants of all the tested fragments. Each fragment was amplified from the variant-enriched pool and sequenced, allowing the discovery of alleles with frequencies as low as 1% in the initial population. Our results support that MRD-based SNP discovery can be used for large-scale discovery of SNPs at low frequencies in a population.

Animals↗
PubMed1977

The use of bovine PPD tuberculin the single caudal fold test to detect tuberculosis in beef cattle.

The efficiency of 2 different doses of bovine PPD tuberculin was compared using the caudal fold test for the detection of tuberculosis in beef cattle. Two matched groups of 98 cattle were selected on the basis of their reactivity to HCSM tuberculin. Cattle in each group were tested with a singl 0.1 ml dose of bovine PPD tuberculin containing either 0.1 mg or 0.2mg bovine PPD respectively. Two further groups of 100 young stock from a herd with an incidence of tuberculosis of less than 0.1% were selected as controls. Tests were interpreted subjectively by palpation and observation and objectively by caliper measurement at 48, 72 and 96h. All cattle were examined post mortem for the presence of visible lesions. The 0.2 mg dose of PPD detected 95% tuberculous cattle and caused false-positive reactions in 19% of cattle without lesions. The 0.1 mg dose detected 80% of tuberculous cattle and caused 11% false-positive reactions. No visible lesions of tuberculosis were found in either of the control groups although 11% reacted to 0.2 mg and 5% to 0.1 mg bovine PPD at 72h. The optimum time for reading tuberculin tests was found to be in the period 48 to 72h after the injection of bovine PPD and subjective interpretation was more efficient than caliper measurement as a means of detection of tuberculous cattle. The 0.2 mg dose of bovine PPD was found to be more specific than HCSM tuberculin.

Animals↗
PubMed1986

Ascorbic acid interference in reagent-strip reactions for assay of urinary glucose and hemoglobin.

Vitamin C (ascorbic acid), commonly taken as a dietary supplement and excreted in the urine, can interfere with peroxidase redox indicator systems such as those used in reagent-strip tests for urinary glucose and hemoglobin. We investigated whether the concentrations of ascorbic acid in urine after modest supplementary doses of vitamin C are high enough to interfere with such dipstick tests. After adding glucose or hemoglobin to urine collected from persons not taking vitamin C and from persons taking 350 to 1000 mg of vitamin C daily, we tested four reagent strips for interference and found that these commonly taken doses did frequently interfere with all test systems examined.

Ascorbic Acid↗
PubMed2002

Immunohistochemical detection of fibronectin and tenascin in incised human skin injuries.

Immunohistochemical detection of molecules involved in inflammatory reaction can be useful for the diagnosis of vitality in skin wounds. We studied the expression of fibronectin (FN) and tenascin (TN) in 58 human skin wounds (48 vital and 10 postmortem). The age of vital injuries ranged from 3 min to 8 h and postmortem specimens were collected after a postinfliction interval of 15-180 min. One hundred thirty-seven formalin-fixed paraffin-embedded sections (mean: 2.3 sections per case) were stained with each of two monoclonal antibodies against FN and TN using the streptABC technique. A reticular staining for FN in wound edge and dermis was observed in 50% of vital specimens versus 0% in postmortem cases. Immunoreactivity was reduced in 10 autolysed cases. FN positivity exclusively at the injury margin was observed in 39.4% of vital wounds and 10% of postmortem cases. TN was negative in all specimens. Vital and postmortem hemorrhage areas showed positivity for FN and TN. Due to its low sensitivity, immunohistochemical analysis of FN is useful for determining vitality only in a minority of cases. Different factors in everyday practice, including autolysis and technical problems often produce false negative reactions with the result that FN cannot be regarded as a reliable parameter of vitality. Positive reactions (network staining) are more valuable than negativity but are not pathognomonic. Both vital and postmortem hemorrhages show an enhanced positivity for FN and TN, thus impeding the diagnosis.

Adult↗
PubMedDate not supplied

Can a positive photopatch test be elicited by subclinical irritancy or allergy plus suberythemal UV exposure?

Photopatch test (PhPT) interpretation is difficult and clinical relevance is not always apparent. A positive PhPT may reflect photocontact allergy or phototoxicity. We hypothesized that it may also reflect the additive or synergistic effects of a suberythemal reaction to a contact irritant [e.g. sodium lauryl sulfate (SLS)] or allergen (e.g. nickel) and suberythemal UV exposure. 10 nickel allergic volunteers had duplicate SLS and nickel series applied on either side of the back for 24 h and 48 h, respectively. After removal, one side was irradiated with 5 J/cm(2) UVA or the dose below the minimal erythema dose for solar-simulated radiation (SSR). The minimal irritancy dose (MID) for SLS and the minimal allergenic dose (MAD) for nickel were determined visually and objectively by erythema meter. While photoaugmentation of subclinical contact allergy or irritancy occurred in some subjects, photosuppression occurred in roughly an equal number. UVA changed the nickel MAD at 48 h in 2 of 5 volunteers but not the SLS MID. SSR changed the nickel MAD in 4 of 5 and the SLS MID in 3 of 5. 2 subjects (none after UVA) showed erythema only in the irradiated set of patches, which could have been interpreted as a positive PhPT. We have demonstrated photoaugmentation and photosuppression of contact allergy and irritancy, which could result in false-positive or false-negative interpretation of PhPTs.

Adolescent↗
PubMed1978

Comparison of miniaturized multitest systems with conventional methodology for identification of Enterobacteriaceae from foods.

Four miniaturized multiple test systems were compared with tube methodology used to identify Enterobacteriaceae encountered in foods. Identification aids supplied with each system were used to assign names to isolates at the species level. For the 129 strains tested, the Minitek system demonstrated a 96.9 percent agreement with reactions in tubed media. The Inolex, Analytab, and PathoTec test systems exhibited 94.3, 93.8, and 92.7 percent agreement, respectively. Analytab identified 96.1 percent of the isolates to the species level, whereas the Minitek, PathoTec, and Inolex systems were able to identify 78.3, 32.6, and 27.1 percent, respectively. The results indicate that the Analytab and Minitek systems are acceptable substitutes for the tube methodology routinely employed in identifying enterics from foods. Although the PathoTec system might be used to screen isolates for their identity, neither the presently available PathoTec nor the Inolex systems should be substituted for current methodology when definitive identification of foodborne organisms is required.

Bacteriological Techniques↗
PubMed1986

Evaluation of six enzyme immunoassays for antibody against human immunodeficiency virus.

Six commercial enzyme immunoassays (EIA) were evaluated in 6488 serum samples, with immunoblot analysis as the confirmatory test for antibodies against human immunodeficiency virus (HIV). The Abbott and Wellcome tests identified all 163 immunoblot-positive samples correctly, whereas the other tests did not detect 1-3 samples. In AIDS patients (predominantly with antibodies to gp41env) Organon's EIA was less sensitive (p less than 0.05) and Wellcome's more sensitive (p less than 0.05) than the immunoblot assay. In symptom-free anti-HIV-positive subjects (antibodies to almost all viral antigens and high titres of anti-p24gag) all the EIA were significantly (p less than 0.05) less sensitive than the immunoblot assay. The frequencies of false-positive reactions in a "tricky" panel of samples from patients with autoimmune and acute viral diseases and in a blood-donor panel were Abbott 9.5%, 0.42%: Organon 1.7%, 0%; Litton 1.0%, 0.4%; Behring 2.7%, 0.06%; Wellcome 0%, 0%; and Pasteur 0%, 0.02%. The results of a seventh EIA (Dupont) were excluded from the study at the company's request. All six EIA evaluated are suitable tests for anti-HIV screening in samples from patients and blood donors.

Acquired Immunodeficiency Syndrome↗
PubMed1978

[Passive haemagglutination test in serodiagnosis of syphilis. Survey of a one-year trial in a venereal diseases prophylactic center (author's transl)].

We report here a one-year study of the reliability of the Treponema pallidum Haemagglutination Test (TPHA) in the serological diagnosis of syphilis. By comparing TPHA data with the diagnosis based on a set of grouped criteria, we were able to determine TPHA accuracy. All studies were conducted at the Antivenereal Prophylactic Center, in Nice, France, on 1,775 sera. The grouped data consisted of:--Serological Test for Syphilis (STS) using cardiolipin antigen,--medical and epidemiological records;--two specific reactions; namely the Fluorescent Antibody Test (FTA) and the Treponema Immobilisation Test (TIT). Reliability is excellent in 98.58 p. 100: the TPHA either proves syphilis or eliminates this diagnosis. The TPHA was particularly useful in investigating "problem sera" for which there existed conflicts in the grouped data. The applicability of TPHA is limited, however, in that it has low sensitivity during early primary syphilis, and it cannot be used to monitor antibodies during treatment. Nevertheless, TPHA, based on a standard specific antigen, is assured of a high place among the tools of serological diagnosis of syphilis because of its high accuracy and sensitivity, its objective and easily read results, and the simplicity of its technique.

False Negative Reactions↗
PubMedDate not supplied

Tuberculin reactivity among health care workers at King Abdulaziz University Hospital, Saudi Arabia.

Tuberculosis is both a nosocomial and an occupational infection. The prevalence of positive tuberculin skin reactions at King Abdulaziz University Hospital, Saudi Arabia, was investigated by testing 298 health care workers. Conventional tuberculin skin testing was performed using 0.1 mL of purified protein derivative injected intracutaneously. After 48-72 hours, induration size was recorded. The prevalence of positive tests (induration > or = 10 mm) was 78.9% overall, 60.0% for Saudi Arabians compared with 81.8% for non-Saudi Arabians (P < 0.01). The mean response size (8.9 +/- 7 mm) for Saudis was also significantly lower than for non-Saudis (13.9 +/- 7 mm, P < 0.001). To enhance the protection of both health care workers and hospitalized patients, effective preventive measures and annual tuberculin testing of health care workers should be considered.

BCG Vaccine↗
PubMed1998

Fecal occult blood testing: clinical value and limitations.

Occult blood in the stool can be detected by chemical (guaiac), heme-porphyrin, or immunological methods. Each has advantages and disadvantages, with the guaiac slide test Hemoccult II (SmithKline Diagnostics) remaining the most widely used. Various technical factors affect its clinical performance, most notably whether the slides are rehydrated before processing; hydration increases test sensitivity for colorectal cancer but markedly decreases specificity, resulting in a large number of false-positive reactions that require invasive and expensive colonic workup. Newer immunological tests generally have high sensitivity, but poor specificity remains an important problem. In clinical screening situations, unhydrated Hemoccult has about 50% sensitivity for colorectal cancers and about 98% specificity. Only 5% to 10% of positive reactions prove due to cancer, however, so the large majority of reactive tests are false positives; this is an important weakness of occult blood screening. Slide hydration detects more tumors, but the predictive value of a positive test for cancer drops to only about 2%, which greatly diminishes the appeal of hydration. Sensitivity of occult blood tests for benign colonic polyps is poor, and most polyps found during workup of a positive reaction are actually detected by chance because of high prevalence in the general population. Controlled clinical trials have now documented that periodic occult blood screening produces a relatively small but significant mortality benefit from colorectal cancer--about 15% to 18% for biennial testing with unhydrated Hemoccult. Aggressive annual screening with hydrated Hemoccult may lower mortality by more than 30% but at a very high cost because of poor specificity and very low predictive value. Regular occult blood testing beginning at age 50 has been endorsed by many professional organizations because of the documented mortality benefit, but poor compliance, high costs, and ethical uncertainties seriously temper its justification. Whether to implement widespread occult blood screening remains a difficult societal decision.

Colorectal Neoplasms↗
PubMed2004

The variability of serological and molecular diagnosis of feline immunodeficiency virus infection.

Diagnosis of feline immunodeficiency virus (FIV) infection by polymerase chain reaction (PCR) has recently become available, but little is known about the performance of this assay. The purpose of this study was to determine the sensitivity and specificity of PCR diagnosis of FIV infection. Replicate aliquots of blood samples from cats identified as FIV positive or negative by 2 previous enzyme-linked immunosorbent assay (ELISA) results, and from clinically healthy dogs, were submitted to different laboratories for FIV serologic diagnosis and PCR. The PCR products obtained in 1 laboratory were sequenced to determine the FIV subtype. The PCR assays correctly identified 100%, 80%, and 50% of the FIV-positive samples, and 100%, 90%, and 70% of FIV-negative samples. Each dog sample was reported as FIV PCR positive at least once, and FIV subtypes A, B, and C were identified. It was concluded that PCR tests currently available for FIV infection are unreliable, with highly variable sensitivity and specificity.

Animals↗
PubMed1994

Reference preparations in the standardisation of HIV-1 PCR--an international collaborative study.

Following the recent developments in diagnostic polymerase chain reaction (PCR) technology, we have assessed a set of HIV-1 DNA reference standards using the first commercial diagnostic test kit for the detection of HIV-1 (Amplicor, Roche) in an international collaborative study. Nineteen laboratories in 11 countries analysed a set of ten (re-coded) HIV-1 DNA reference standards, whose performance had been validated in a previous collaborative study (Bootman and Kitchin, 1992). Results from the current study show that, using the diagnostic kit, 84% of laboratories (16/19) obtained correct diagnoses for all ten test samples. One additional laboratory failed only to detect the sample containing ten copies of target template. Test results from the remaining two laboratories were declared void in accordance with the Amplicor quality control guidelines.

DNA, Viral↗
PubMed2004

Fetal origin of single nucleated erythroblasts and free DNA in the peripheral blood of pregnant women.

OBJECTIVES: To investigate the feasibility of using single fetal nucleated erythroblasts (FNRBCs) and free DNA in maternal blood for non-invasive prenatal diagnosis. METHODS: Single FNRBCs were isolated from 51 of 116 samples of maternal blood analyzed by micromanipulation after density gradient centrifugation. Furthermore, the nested polymerase chain reaction (PCR) method was used to amplify the SRY gene of single FNRBCs. Primer extension pre-amplification and nested PCR were used to amplify the SRY gene of the plasma DNA extracted from 65 samples of maternal blood. RESULTS: The detection rate of single FNRBCs was 90.20% (46/51). The concordance rates between real fetal sex and sex determined by amplification of the SRY gene from single cells and from free DNA analysis were 82.61% (38/46) and 90.77% (59/65), respectively. CONCLUSIONS: Single nucleated erythroblasts and free DNA in maternal blood are of fetal origin and can be valuable fetal material sources for non-invasive prenatal diagnosis.

Adult↗