Counter Current Line Absorption Immunoelectrophoresis is an Alternative Diagnostic Screening Test to Counter Current Immunoelectrophoresis in Aleutian Disease (AD) Eradication Programs

Counter current immunoelectrophoresis (CCIE) is the diagnostic method used in the ongoing Aleutian disease virus eradication program on Danish mink farms. There has been an increasing demand for an alternative diagnostic test especially to evaluate suspected false positive CCIE reactions. We compared test results of a number of negative and positive mink sera in indirect counter current immunoelectrophoresis (ICCIE), counter current line absorption immunoelectrophoresis (CCLAIE) and radio immuno assay (RIA) with test results from counter current immunoelectrophoresis and found that counter current line absorption immunoelectrophoresis is the best alternative diagnostic screening test to counter current immunoelectrophoresis for Aleutian disease eradication programs. Not only proved the CCLAIE test to be useful for evaluation of doubtfully positive CCIE reactions, but it was found to have a higher sensitivity than the CCIE test.     

Development of a Multiplexed Bead-Based Suspension Array for the Detection and Discrimination of Pospiviroid Plant Pathogens

Efficient and reliable diagnostic tools for the routine indexing and certification of clean propagating material are essential for the management of pospiviroid diseases in horticultural crops. This study describes the development of a true multiplexed diagnostic method for the detection and identification of all nine currently recognized pospiviroid species in one assay using Luminex bead-based suspension array technology. In addition, a new data-driven, statistical method is presented for establishing thresholds for positivity for individual assays within multiplexed arrays. When applied to the multiplexed array data generated in this study, the new method was shown to have better control of false positives and false negative results than two other commonly used approaches for setting thresholds. The 11-plex Luminex MagPlex-TAG pospiviroid array described here has a unique hierarchical assay design, incorporating a near-universal assay in addition to nine species-specific assays, and a co-amplified plant internal control assay for quality assurance purposes. All assays of the multiplexed array were shown to be 100% specific, sensitive and reproducible. The multiplexed array described herein is robust, easy to use, displays unambiguous results and has strong potential for use in routine pospiviroid indexing to improve disease management strategies.     

The mouse spot test. Evaluation of its performance in identifying chemical mutagens and carcinogens

The published results on 60 chemicals and X-rays investigated in the mouse spot test were compared with data on the same chemicals tested in the bacterial mutation assay (Ames test) and lifetime rodent bioassays. The performance of the spot test as an in vivo complementary assay to the in vitro bacterial mutagenesis test reveals that of 60 agents, 38 were positive in both systems, 6 were positive only in the spot test, 10 were positive only in the bacterial test and 6 were negative in both assays. The spot test was also considered as a predictor of carcinogenesis; 45 chemicals were carcinogenic of which 35 were detected as positive by the spot test and 3 out of 6 non-carcinogens were correctly identified as negative. If the results are regarded in sequence, i.e. that a positive result in a bacterial mutagenicity test reveals potential that may or may not be realized in vivo, then 48 chemicals were mutagenic in the bacterial mutation assay of which 38 were active in the spot test and 31 were confirmed as carcinogens in bioassays. 12 chemicals were non-mutagenic to bacteria of which 6 gave positive responses in the spot test and 5 were confirmed as carcinogens. These results provide strong evidence that the mouse coat spot test is an effective complementary test to the bacterial mutagenesis assay for the detection of genotoxic chemicals and as a confirmatory test for the identification of carcinogens. The main deficiency at present is the paucity of data from the testing of non-carcinogens. With further development and improvement of the test it is probable that the predictive performance of the assay in identifying carcinogens should improve, since many of the false negative responses may be due to inadequate testing.     

Evaluation of an indirect serum ELISA and a bacteriological faecal culture test for diagnosis of Salmonella serotype Dublin in cattle using latent class models

AIMS: To evaluate a conventional bacteriological test based on faecal culture and an indirect serum ELISA for detection of S. Dublin infected cattle. To compare the predictive values of the two tests in relation to the prevalence. METHODS AND RESULTS: A total of 4531 paired samples from cattle in 29 dairy herds were analysed for presence of S. Dublin bacteria in faeces and immunoglobulins directed against S. Dublin lipopolysaccharide in an indirect serum ELISA. Sensitivity and specificity were estimated at two ELISA cut-off values using a validation method based on latent class models, which presumably provides less biased results than traditional validation methods. Stratification of data into three age groups gave significantly better estimates of test performance of the ELISA. Receiver operating characteristic (ROC) curves were constructed for comparison of overall performance of the ELISA between the three age groups. The sensitivity of the faecal culture test was low (6-14%). ELISA appeared to have a higher validity for animals aged 100-299 days of age than older or younger animals. Overall, the negative predictive value of the ELISA was 2-10 times higher than for the faecal culture test at realistic prevalence of infection in the test population. CONCLUSIONS: The diagnostic sensitivity of the faecal culture test for detection of S. Dublin is poor, the specificity is 1. The superior sensitivity and negative predictive value of the serum ELISA makes this test preferable to faecal culture as an initial screening test and for certification of herds not infected with S. Dublin. SIGNIFICANCE AND IMPACT OF THE STUDY: A quantitative estimate of the sensitivity of a faecal culture test for S. Dublin in a general population was provided. ELISA was shown to be an appropriate alternative diagnostic test. Preferably, samples from animals aged 100-299 days of age should be used as these give the best overall performance of the ELISA. Plots of ROC curves and predictive values in relation to prevalence facilitates optimisation of the ELISA cut-off value.     

Immunodiagnosis of sexually transmitted disease

Methods for detecting microbial antigens in clinical specimens offer an alternative to culture in the diagnosis of some sexually transmitted diseases. Developers of the immunologic methods are faced with a number of problems in evaluating the new tests. Traditionally, these tests are compared to culture as the "gold standard." Unfortunately, culture for Neisseria gonorrhoeae or Chlamydia trachomatis--the two agents most commonly sought--is considerably less sensitive than 100 percent. Immunologic methods may appear to produce false positives when the paired specimens are actually false-negative cultures. Another source of discordant results is sampling variation. These considerations, however, will not account for all false-positive results. Even the best non-culture methods have a low rate of false-positive results. If a new test has a specificity of 97 percent, it, by definition, yields approximately 3 percent false-positive reactions. In low-prevalence settings this false-positive rate will create problems in interpreting the results. For example, in a population with 3 percent prevalence of infection, a positive result in a 97 percent specificity test could only have a predictive value of 50 percent. Most testing for STD agents is performed in low-prevalence settings. None of the currently available immunodiagnostic procedures has a performance profile that suggests it will be satisfactory for diagnostic use in the low-prevalence setting.     

What is the role of histidine in studies of faecal mutagenicity?

Mutagenicity testing can be used to assay faeces for genotoxic substances and the results are reported to correlate with population risk for colorectal cancer (Ehrich et al., 1979). It has been suggested that histidine in faeces may cause false positive results (Venitt and Bosworth, 1983). To determine the relationship between histidine and false positive mutagenicity assays aliquots of non-mutagenic faecal extract and saline were supplemented with histidine and subjected to the Ames Salmonella/mammalian microsome mutagenicity assay (Ames et al., 1975). Using high-pressure liquid chromatography the analytical recovery of histidine from water and faecal extract supplemented with histidine was equivalent (r = 0.998, p less than 0.001). Histidine was measured in faecal extracts (1 in 10 dilutions) from 35 volunteers, 10 patients with inflammatory bowel disease and 4 with rectal cancer. These extracts were also assayed for mutagens using the Salmonella/mammalian microsome mutagenicity assay. None of the faecal extracts gave mutagenicity ratios above 2. Faecal extracts from volunteers were free of detectable histidine. Although 9 of those from inflammatory bowel disease patients contained histidine (mean +/- SEM 255 +/- 34 mumoles l-1) as did 1 extract from a rectal cancer patient (50 mumoles l-1), none contained sufficient histidine to give a false positive Salmonella/mammalian microsome mutagenicity assay result (800 mumoles l-1 in test solution). Our results do not implicate histidine as a cause of error in faecal mutagenicity testing by the Salmonella/mammalian microsome mutagenicity assay.     

Evaluation of PCR on bronchoalveolar lavage fluid for diagnosis of invasive aspergillosis: a bivariate metaanalysis and systematic review

Background

Nucleic acid detection by polymerase chain reaction (PCR) is emerging as a sensitive and rapid diagnostic tool. PCR assays on serum have the potential to be a practical diagnostic tool. However, PCR on bronchoalveolar lavage fluid (BALF) has not been well established. We performed a systematic review of published studies to evaluate the diagnostic accuracy of PCR assays on BALF for invasive aspergillosis (IA).

Methods

Relevant published studies were shortlisted to evaluate the quality of their methodologies. A bivariate regression approach was used to calculate pooled values of the method sensitivity, specificity, and positive and negative likelihood ratios. Hierarchical summary receiver operating characteristic curves were used to summarize overall performance. We calculated the post-test probability to evaluate clinical usefulness. Potential heterogeneity among studies was explored by subgroup analyses.

Results

Seventeen studies comprising 1191 at-risk patients were selected. The summary estimates of the BALF-PCR assay for proven and probable IA were as follows: sensitivity, 0.91 (95% confidence interval (CI), 0.79–0.96); specificity, 0.92 (95% CI, 0.87–0.96); positive likelihood ratio, 11.90 (95% CI, 6.80–20.80); and negative likelihood ratio, 0.10 (95% CI, 0.04–0.24). Subgroup analyses showed that the performance of the PCR assay was influenced by PCR assay methodology, primer design and the methods of cell wall disruption and DNA extraction.

Conclusions

PCR assay on BALF is highly accurate for diagnosing IA in immunocompromised patients and is likely to be a useful diagnostic tool. However, further efforts towards devising a standard protocol are needed to enable formal validation of BALF-PCR.     

The Evaluation and Interpretation of Cervical Cytology: Application of the Likelihood Ratio Concept

The Papanicolaou smear (Pap test), used for the detection and prevention of neoplastic lesions of the cervix, is known to have both false negative and false positive results. Proper handling of the diagnostic uncertainty resulting from these errors demands quantification of flaws. Traditionally, sensitivity, specificity and predictive values are used for that aim. In this study another approach is advocated, namely the use of the likelihood ratio. For cervical cytology this ratio is the quotient of the probability of a Pap class within the diseased population to the probability of that same Pap class within the non-diseased group. This approach enables the characterization of each Pap class separately, and is therefore much better for clinical interpretation of the result. It is also a superior approach for quality assessment.     

High sensitivity of both sequencing and real‐time PCR analysis of KRAS mutations in colorectal cancer tissue

The KRAS mutation status predicts the outcome of treatment with epidermal growth factor receptor targeted agents, and therefore the testing for KRAS mutations has become an important diagnostic procedure. To optimize the quality of this test, we compared the results of the two most commonly used KRAS mutation tests, cycle sequencing and a real‐time PCR‐based assay, in DNA extracted from formalin‐fixed paraffin‐embedded (FFPE) colorectal cancer samples of 511 patients. The results were interpreted in the context of the tumour cell percentage and the assay parameters. In 510 samples KRAS mutation status assessment was successful. A KRAS mutation was detected in 201 tumours (39.4%). Sequencing and the real‐time PCR‐based assay generated the same result in 486 samples (95.3%). The sequencing result was considered false positive in one (0.2%) and false negative in nine samples (1.8%). The assay result was considered false positive in six (1.2%) and false negative in seven samples (1.4%). Explanations for discrepant test results were a higher sensitivity of the assay in samples with a low tumour cell percentage, occurrence of mutations that are not covered by the assay and δ Ct values approximating the cut‐off value of the assay. In conclusion, both sequencing and the real‐time PCR‐based assay are reliable tests for KRAS mutation analysis in FFPE colorectal cancer samples, with a sensitivity of 95.5% (95% confidence interval [CI] 91.7–97.9%) and 96.5% (95% CI 93.0–98.6%), respectively. The real‐time PCR based assay is the method of choice in samples with a tumour cell percentage below 30%.     

Screening for possible human carcinogens and mutagens. False positives, false negatives: statistical implications

A screening method aimed at identifying potential human carcinogens using either animal cancer bioassays or short-term genotoxic assays has 4 possible results: true positive, true negative, false positive and false negative. Such a categorisation is superficially similar to the results of hypothesis testing in a statistical analysis. In this latter case the false positive rate is determined by the significance level of the test and the false negative rate by the statistical power of the test. Although the two types of categorisation appear somewhat similar, different statistical issues are involved in their interpretation. Statistical methods appropriate for the analysis of the results of a series of assays include the use of Bayes' theorem and multivariate methods such as clustering techniques for the selection of batteries of short-term test capable of a better prediction of potential carcinogens. The conclusions drawn from such studies are dependent upon the estimates of values of sensitivity and specificity used, the choice of statistical method and the nature of the data set. The statistical issues resulting from the analysis of specific genotoxicity experiments involve the choice of suitable experimental designs and appropriate analyses together with the relationship of statistical significance to biological importance. The purpose of statistical analysis should increasingly be to estimate and explore effects rather than for formal hypothesis testing.     

Performance of Thyroid-Stimulating Immunoglobulin Bioassay and Thyrotropin-Binding Inhibitory Immunoglobulin Assay for the Diagnosis of Graves' Disease in Patients With Active Thyrotoxicosis

ObjectiveGraves' disease (GD) is caused by the stimulation of thyrotropin receptors by autoantibodies. We compared the diagnostic accuracy of the thyroid-stimulating immunoglobulin (TSI) bioassay and thyrotropin-binding inhibitory immunoglobulin (TBII) assay in differentiating GD from other causes of thyrotoxicosis.MethodsWe retrospectively evaluated 493 patients with thyrotoxicosis who were tested with the third-generation TSI and TBII assays simultaneously. Patients were classified according to the clinical, histopathologic, and imaging criteria into the following groups: positive reference group (PRG) (patients with GD), negative reference group (NRG) (patients without GD), and inconclusive group (patients without a definitive diagnosis).ResultsTSI and TBII assays were concordant in 88% of the cases and showed a strong positive correlation (r_s = 0.844, P < .01). When analyzed collectively, TSI and TBII assays confirmed the diagnosis of GD in 79% of the PRG cases and excluded GD in 92.5% of patients in NRG. Combined TSI and TBII assays or TBII assay alone showed similar accuracy to the diagnosis of GD (81.4% and 77.5%, respectively). Tests in 40 of 191 patients in PRG were negative for both TSI and TBII assays, whereas 3 of 40 cases in NRG had at least 1 positive thyrotropin receptor antibody test. False-negative cases were associated with subclinical hyperthyroidism, normal radionuclide uptake, longer duration of thyrotoxicosis, and absence of goiter or Graves' ophthalmopathy.ConclusionTSI and TBII assays showed similar performance in differentiating GD from other causes of thyrotoxicosis in a real-world sample of patients with active thyrotoxicosis. In combination, both tests showed little benefit compared with the TBII assay alone. Thyrotropin receptor antibody assay results should be carefully interpreted in patients with mild GD or longstanding disease.     

A rapid immunochromatographic assay for the detection of Mycobacterium tuberculosis antigens in pulmonary samples from HIV seropositive patients and its comparison with conventional methods

As tuberculosis generates a highly heterogeneous antibody repertoire, its diagnosis requires tests based on cocktails of antigens. We describe a new, rapid method called rapid immunochromatographic assay (RICA) for cocktail-based diagnosis, which can detect Mycobacterial antigens in sputum specimens. Six antigenic fractions of pathogenic Mycobacterium tuberculosis were used in combination as the capture antigens in the control line of the flow-through assay. Antigen detection of 200 sputum samples from HIV seropositive patients by RICA assay gave a sensitivity of 97.9%, specificity of 99.0%, positive predictive value of 98.9%, negative predictive value of 98.0%, false positive rate of 0.9%, false negative rate of 2.0%, prevalence rate of 49%, likelihood ratio for positive results 97 and likelihood ratio for negative results 0.02. The combination of RICA and AFB staining gave a sensitivity of 100%, specificity of 100%, positive predictive value of 100%, negative predictive value of 100%, false positive rate of 0%, false negative rate of 0%, likelihood ratio for negative results 0. The assay was simple, rapid and economical for the detection of M. tuberculosis infection and suitable for large scale screening of samples in endemic areas without any sophisticated equipment. The results of the assay proved to be superior to conventional methods and combined with clinical data, could form the basis for starting an earlier course of treatment.     

Frequency of False Positive Rapid HIV Serologic Tests in African Men and Women Receiving PrEP for HIV Prevention: Implications for Programmatic Roll-Out of Biomedical Interventions

Background

Rapid HIV assays are the mainstay of HIV testing globally. Delivery of effective biomedical HIV prevention strategies such as antiretroviral pre-exposure prophylaxis (PrEP) requires periodic HIV testing. Because rapid tests have high (>95%) but imperfect specificity, they are expected to generate some false positive results.

Methods

We assessed the frequency of true and false positive rapid results in the Partners PrEP Study, a randomized, placebo-controlled trial of PrEP. HIV testing was performed monthly using 2 rapid tests done in parallel with HIV enzyme immunoassay (EIA) confirmation following all positive rapid tests.

Results

A total of 99,009 monthly HIV tests were performed; 98,743 (99.7%) were dual-rapid HIV negative. Of the 266 visits with ≥1 positive rapid result, 99 (37.2%) had confirmatory positive EIA results (true positives), 155 (58.3%) had negative EIA results (false positives), and 12 (4.5%) had discordant EIA results. In the active PrEP arms, over two-thirds of visits with positive rapid test results were false positive results (69.2%, 110 of 159), although false positive results occurred at <1% (110/65,945) of total visits.

Conclusions

When HIV prevalence or incidence is low due to effective HIV prevention interventions, rapid HIV tests result in a high number of false relative to true positive results, although the absolute number of false results will be low. Program roll-out for effective interventions should plan for quality assurance of HIV testing, mechanisms for confirmatory HIV testing, and counseling strategies for persons with positive rapid test results.     

反向间接胶乳凝集试验法检测粪便A型产气荚膜梭菌肠毒素的结果及评价

本文以１０种５２株供试菌分别与７个不同年龄组的健康人粪便混合,共配成３６４份模拟标本,采用反向间接胶乳凝集（ＲＰＬＡ）试验法与生物学试验法（小鼠致死试验、豚鼠皮肤血管透性因子试验,Ｖｅｒｏ细胞毒性试验）检测各标本中的Ａ型产气荚膜梭菌肠毒素（简称Ｃｐ－Ｅｎｔ）。除产气荚膜梭菌之外的其他菌种培养液２３８份标本（３４株）,ＲＰＬＡ与生物学试验结果完全一致,均为阴性。产气荚膜梭菌１２６份标本（１８株）中有７０份标本的ＲＰＬＡ同生物学诸法完全一致地检出了Ｃｐ－Ｅｎｔ．有１株７份标本（ＣｐＮＣＴＣ８７９７）的ＲＰＬＡ为阳性,而各生物学试验却均为阴性,该菌株经ＰＣＲ检查证明确为肠毒素原性产气荚膜梭菌,表明ＲＰＬＡ比生物学试验法更灵敏。有５株（ＣｐＮＣＴｃ８２３８,ＣｐＮＣＴＣ１０６１１,ＣｐＮＣＴＣ１０６１４,ＣｐＮＣＴＣ１０６１２,ＣｐＬ－５２）３５份标本ＲＰＬＡ与各生物学试验结果均为阴性,但经ＰＣＲ检吉证明该５株菌均为肠毒素原性产气荚膜梭菌,后经超声波破碎菌体提取物对其中部分菌株进行试验的结果仍然显示了ＲＰＬＡ与生物学法的一致性。有２株（ＣｐＮＣＴＣ８６８６,ＣｐＮＣＴＣ８４４９）１４份标本的所有结果均为阴性,ＰＣＲ     

Evaluation of rapid test Assure Helicobacter pylori for diagnosis of H. pylori in pediatric population

Non-invasive tests are needed to assess Helicobacter pylori infection, especially to screen a pediatric population. Assure H. pylori Rapid Test (Genelabs Diagnostics, Singapore) is an immunochromatographic assay device intended for the rapid detection of antibodies to H. pylori in human serum, plasma or whole blood. The aim of this study was to evaluate the performance of the rapid test, Assure H. pylori, in the diagnosis of H. pylori infection in children, using a Portuguese pediatric population. The study group included 130 children with age ranging from 1 to 14 years old (average age 9.2+/-3.1 years). According to the gold standard, 70 of the 130 patients studied were H. pylori positive and 60 were H. pylori negative. Using Assure H. pylori Rapid Test (Genelabs Diagnostics, Singapore), 53 sera had a positive result after 15 min (resulting in 17 false negatives) and 57 sera a negative result (resulting in 3 false positives). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the test were 75.7%, 95.0%, 94.6% and 77.0% respectively. When a longer read time of 45 min is considered, the rapid test revealed a good performance (sensitivity 98.6% and specificity 95%) in the evaluation of the H. pylori infection in a pediatric population. In conclusion, the test showed a good performance, suggesting its applicability as a screening method for the H. pylori infection.     

Mutant cells defective in DNA repair pathways provide a sensitive high-throughput assay for genotoxicity

Chemicals used industrially and commercially are required by law to be assessed for their genotoxic potential. However, all currently used assays have major limitations and despite intense effort, there is no universal agreement on which tests should be employed, or how to interpret results. We have developed a new assay system using the chicken DT40 B cell line that offers a number of significant advantages over current methodologies. Our assay could provide enhanced sensitivity using genetically defined and phenotypically characterized mutants defective in DNA repair pathways. Furthermore, analysis of the mutants, using DNA repair proficient wild-type cells as a negative control, minimizes false negative outcomes. Assessing the different responses of a panel of mutants representative of all repair pathways, mechanistic detail of genotoxicity can be determined. This unique feature, as well as reducing the false positive rate, strengthens positive identifications and is useful when extrapolating results to the human context. Our panel of mutants is likely to be useful in screening large compound libraries for an emerging class of chemotherapeutic drugs, which includes inhibitors of DNA repair enzymes such as PARP and DNA polymerases.     

Sample size for positive and negative predictive value in diagnostic research using case-control designs

Important properties of diagnostic methods are their sensitivity,specificity, and positive and negative predictive values (PPVand NPV). These methods are typically assessed via case–controlsamples, which include one cohort of cases known to have thedisease and a second control cohort of disease-free subjects.Such studies give direct estimates of sensitivity and specificitybut only indirect estimates of PPV and NPV, which also dependon the disease prevalence in the tested population. The motivatingexample arises in assay testing, where usage is contemplatedin populations with known prevalences. Further instances includebiomarker development, where subjects are selected from a populationwith known prevalence and assessment of PPV and NPV is crucial,and the assessment of diagnostic imaging procedures for rarediseases, where case–control studies may be the only feasibledesigns. We develop formulas for optimal allocation of the samplebetween the case and control cohorts and for computing samplesize when the goal of the study is to prove that the test procedureexceeds pre-stated bounds for PPV and/or NPV. Surprisingly,the optimal sampling schemes for many purposes are highly unbalanced,even when information is desired on both PPV and NPV.     

Comparison of PCR and clinical laboratory tests for diagnosing <Emphasis Type="Italic">H. pylori</Emphasis> infection in pediatric patients

Background

Histology and/or culture are generally considered the gold standard for the detection of H. pylori infection. Especially in children, these tests may result in a false negative outcome because of patchy distribution of the organism in the stomach mucosa. We have developed a PCR assay utilizing nested primer pairs directed against a subunit of the H. pylori urease gene (ureA). As part of a prospective evaluation of diagnostic tests to aid in detecting H. pylori infection in children, the aim of this study was to compare our PCR and Western blot assays with results obtained from histologic examination of biopsy specimens, rapid urease tests, and an FDA approved serologic assay and published PCR results to determine if we could validate the assays for diagnostic use on our patient population.

Results

Gastric biopsy specimens obtained from 101 pediatric patients were evaluated for the presence of H. pylori using histologic techniques, rapid urease (CLOtest) test and the PCR assay. Serum samples from each patient were assayed using both ELISA and Western Blot for antibodies to H. pylori. A total of 32 patients tested were positive by at least one of the methods evaluated. Thirteen patients had positive histology, 13 had a positive CLOtest, and 17 patients had positive H. pylori PCR. Out of the 13 CLO positive patients, 12 were positive by histologic analysis and all 13 were positive by PCR. Results of serologic tests on the same population did not correlate well with other assays. Twenty-eight patients showed serologic evidence of H. pylori infection, of which 9 were both CLO and histology positive and 12 were positive by PCR. Of the seropositive patients, 26 were ELISA positive, 13 were positive by Western blot, and 11 by both serologic methods.

Conclusions

The results obtained suggest that our nested PCR assay has the specificity and sensitivity necessary for clinical application when compared to standard histologic examination and rapid urease test. In addition, we found the current commercially available approved ELISA method appears unable to accurately detect H. pylori in this population. The Western blot assay yielded better concordance with CLOtest and histology, but not as good as the nested PCR assay.

     

Mutation detection, interpretation, and applications in the clinical laboratory setting

Mutation detection plays an increasingly significant role in clinical diagnostic testing, posing formidable challenges for laboratories. The expanding indications for clinical molecular testing and the nuances of interpreting test results are discussed. Methods for screening mutation detection platforms and monitoring assay reliability are presented, and results of platform comparisons are described. The potential for irrevocable medical interventions following a positive mutation analysis is highlighted to stress the imperative for accuracy in mutation detection and vigilance in the clinical arena.