地中海贫血产前筛查的循证检验

目的评价红细胞平均体积(MCV)、红细胞脆性试验和血红蛋白(Hb)电泳在地中海贫血产前筛查中的应用价值,为临床寻找一个较理想的地贫产前筛查的检验方法。方法选择2年间在我院进行系统产前检查的孕妇2060例资料,对已被基因诊断证实的210例地中海贫血孕妇的筛查实验结果进行回顾性分析。结果MCV、红细胞脆性及Hb电泳单项检测在地中海贫血产前筛查的灵敏度和特异度分别为:97.6%、89.5%、90.0%及76.0%、89.3%、97.3%;MCV与Hb电泳、红细胞脆性与Hb电泳两项平行联合检测的灵敏度及特异度分别为:100.0%、99.0%及86.7%、89.3%,系列联合检测的灵敏度及特异度分别为:89.0?.1%及99.7%、100.0%。MCV、红细胞脆性及Hb电泳三项平行联合检测的灵敏度及特异度分别为:100.0%、79.7%;三项系列联合检测的灵敏度及特异度分别为:86.7%、100.0%。经u检验,平行联合检测的灵敏度与各单项检测灵敏度之间、系列联合检测的特异度与各单项检测特异度之间差异有统计学意义(P<0.05)。结论MCV、红细胞脆性及Hb电泳三项联合检测是地中海贫血产前筛查的最理想的试验方法。     

Diagnostic implications of kinetics of immunoglobulin M and A antibody responses to Toxoplasma gondii.

We evaluated immunoglobulin M (IgM) and IgA assays that could improve the predictive value for recently acquired toxoplasma infection for patients with positive screening test results. Follow-up sera were collected from 82 patients whose initial serum specimen had a reactive anti-Toxoplasma gondii IgM result. According to the evolution of the immune response, patients were divided retrospectively into two groups: one in which a recent infection was unlikely and the other one with an evolving immune response suggestive of recent toxoplasma infection. All IgM and one of three IgA assays used in the study are suitable for screening pregnant patients, with a negative predictive value of 100%. The predictive value of positive results is much lower because of the low prevalence of acute toxoplasmosis in pregnant women and the long persistence of IgM after acute infection. In the present study, all except one IgM enzyme immunoassay remained positive well beyond 6 months after the initial sample was tested. The IgM immunofluorescence test had the shortest persistence of positivity in most cases. IgA tests were either too insensitive or remained reactive too long to be useful for screening pregnant patients. Interpreting enzyme immunoassays with modified cutoff values and the combination of two tests could improve the predictive value of positive results to about 80% in terms of recent infection.     

Spectrum of anemia in pregnant Indian women and importance of antenatal screening

Anemia is a common health problem but control of anemia in pregnant women is less well studied. The purpose was to study prevalence of anemia in young pregnant women, correlate with indices and study significance of identification of hemoglobinopathies. Of the 120 pregnant women, Hb was less than 8 g% in 58 (44.2%). Seventy-eight (65%) had iron deficiency, 22 (18.3%) had dimorphic anemia, and 14 (11.6%) had hemolytic anemia. Megaloblastic anemia was present in 6 (5%). Of hemolytic anemia, 50% were thalassemia trait. MCV< 76 fl was observed in 88 (73.3 %) cases. MCV<76 fl and MCH < 27 pg had 100 % sensitivity and 28.7 % specificity for screening of beta-thalassemia trait. NESTROFT had comparable sensitivity but lower specificity (14.9%). Sixty-three percent (60/78) of IDA had increased RDW whereas 78 % (11/14) of hemolytic anemia had RDW value in normal range (p value< 0.05). MCV/RBC of <14 was more specific parameter (96.8%) for beta-thalassemia trait. Four high-risk couples were identified. Thus, moderate to severe anemia was observed in most pregnant women. Hemoglobinopathies should be screened in antenatal clinics to identify the couples that would need a prenatal test. A lower MCV/RBC with RDWin the normal range may be useful in screening for thalassemia trait in pregnant women.     

Advantages in the use of high performance liquid chromatography technique for screening hemoglobinopathies in Venezuela

The hemoglobinopathies are a very heterogeneous group of congenital hemolytic anemias, which includes hemoglobin (Hb) variants, thalassemia and hereditary persistence of fetal hemoglobin (HPFH). The aim of this study was to determine the frequency of hemoglobinopathies using the High Performance Liquid Chromatography (HPLC-CE) technique with the beta-thalassemia Short Program of Variant* Bio Rad. Four thousand blood samples from anemic patients from the Laboratorio de Investigación de Hemoglobinas Anormales, Hospital Universitario de Caracas were studied. Twenty six percent of the anemia patients had hemoglobinopathies. The Hb S was the most frequent variant found, followed by the Hb C and Hb D. Also we observed the association of beta thalassemia with Hb S and Hb C. The quantification of the Hb A by HPLC-CE allowed us to classify the double heterozygote Hb S-Beta Thalassemia in Hb S-beta+ Tal Type 1, Hb S-beta+ Tal Type 2, Hb S-beta(0) Thalassemia. The double heterozygote patients with Hb C-Beta thalassemia were also classified. The HPLC-CE is a rapid, reproducible and precise technique. The reliability of HbA2 measurement by HPLC for the detection of beta thalassaemia without any false positive or false negative results is of great advantage. HPLC may be an appropriate method for rapid screening in population surveys for beta thalassemia and hemoglobin variants carriers. Due to the high incidence of cases, in our country this is very important for their clinical management and the genetic and anthropological impact of an early and precise diagnosis.     

基于社区水平的珠海市大人群地中海贫血的遗传筛查和产前诊断

目的 阐述在广东省珠海市开展基于社区的控制重型α和β地中海贫血(简称地贫)的预防模式.方法 构建由6家医院组成的二级地贫遗传服务网络,以珠海市婚前医学或产前检查人群作为筛查对象,采用常规杂合子筛查策略,以标准的血液学分析流程进行α和β地贫特征的筛查.对所有地贫疑诊对象进行随访和遗传咨询,并采用基于PCR的分子诊断技术对高风险夫妇进行确诊.在知情同意和选择的情况下,对高风险妊娠实施产前基因诊断并通过选择性引产淘汰受累的重型地贫胎儿.结果 从1998年1月至2005年12月,共筛查了85522例拟婚育龄青年和10439例孕妇,婚检地贫筛查覆盖率达到71.38%.在6563例地贫筛查阳性的病例中,α和β地贫分别为4312例(4.5%)和2251例(2.3%);总计发现148对有生育重型地贫儿可能的高风险夫妇(α地贫103对,β地贫45对),其中有142对(95.9%)高风险夫妇进行了产前诊断(α地贫98例,β地贫44例).本项目启动后共减少了41例重型地贫患儿的出生,其中包括Hb Barts水肿胎23例、Hb H病4例和重型β-地贫14例.结论 这是我国首次基于社区水平的、在拥有129万人口的珠海市实施的前瞻性α和β地贫预防监控计划.这一预防模式对我国其他地贫高发区和其他发展中国家开展地贫和其他血红蛋白病的预防有着重要的借鉴意义.     

Field performance of the INSTI HIV-1/-2 antibody test in two South African antenatal clinics

This was a prospective study that assessed field performance of the INSTI HIV-1/-2 antibody test (INSTI test) in two antenatal clinics in South Africa (SA). INSTI test was evaluated against rapid tests used at these clinics, and pooled nucleic acid amplification testing (NAAT) performed for individuals with negative rapid tests. Three hundred and eighty-six pregnant women were enrolled; 334 (86.5%) with negative results on the screening rapid test, and 52 (13.5%; 95% confidence interval [CI]: 10.2–17.3%) with positive results on screening and confirmatory rapid tests. INSTI test yielded the same results as other rapid tests in all participants, thus showing a 100% sensitivity (95% CI: 93.2–100.0%) and specificity (95% CI: 98.9–100.0%). Pooled NAAT was performed for 290 participants who had negative rapid tests, and yielded negative results in all pools. These data show excellent field performance of the INSTI test, and highlight that this test can be implementedat SA clinics.     

Modified latex agglutination test for antibodies to Toxoplasma gondii in eluates from Guthrie cards.

AIMS: To determine whether the Eiken particle agglutination test could be modified to make it sufficiently sensitive to screen blood samples collected on Guthrie cards for the presence of antibodies to Toxoplasma gondii; to evaluate the specificity of the modified system; and to compare seroepidemiological data on the prevalence of T gondii in pregnant women. METHODS: Simulated dried blood spots were prepared from sera from pregnant women booking for antenatal care. Eluates from the simulated dried blood spot cards and sera were tested in parallel using the modified test (1 in 5 dilution of latex) and the standard assay (neat latex particles) and endpoints determined. Guthrie card eluates, from neonates in three Thames regions, were then tested using the modified test. RESULTS: The modified test produced a 4.21-fold increase in antibody titre in 85 sera when tested in parallel with the standard test. Eluates of 168/170 from simulated dried blood spots derived from seropositive patients gave a positive result in the modified test. The two eluates which gave a negative result were derived from patients with an equivocal titre of 1/16 in the standard serum test. Of the eluates derived from serum negative patients all 103 were negative at a dilution of 1 in 4 in the modified test. The seroprevalence of antibodies to T gondii in pregnancy was 21.8% using the standard test. A similar value of 20.5% was obtained when dried blood spots from neonates in a similar region of London were tested by the modified test. CONCLUSIONS: The modified Eiken Toxo-reagent test is sensitive, simple, and economic for screening large numbers of dried blood spots. The procedure could be easily semiautomated and the technique applied to the mass screening of neonatal blood samples collected on Guthrie cards to determine the seroprevalence of T gondii in pregnant women.     

Evaluation of various screening tests to detect asymptomatic bacteriuria in pregnant women

To evaluate the diagnostic efficacy of various screening tests in detecting asymptomatic bacteriuria among pregnant women. Clean catch midstream urine specimens were collected from 630 consecutive pregnant women and processed. Forty-four (7.4%) of the urine samples were culture positive, with Escherichia coli as the predominant organism isolated (57.4%). The results of the four screening tests, viz., Gram's staining of uncentrifuged urine, pus cell count, nitrite test and leukocyte esterase (LE) test, were compared against urine culture. Gram's stain of the uncentrifuged urine was found to be the single most useful test with a sensitivity and negative predictive value (NPV) of 85.1% and 98.8%, respectively. Pus cell count was the least sensitive. Neither the nitrite test nor the LE test alone was sensitive enough with 74.4% and 61.7%, respectively. However, when either or both tests positive were considered, it increased the sensitivity and NPV comparable with Gram's staining results, with 82.9% and 98.8%, respectively. With the potential to be used as an office diagnostic procedure, the combined nitrite and LE dipstick test may provide an acceptable alternative.     

Immunisation anti-érythrocytaire dans les hémoglobinopathies : à propos de 84 cas

AimsTo estimate the rate of red cell immunization in hemoglobinopathies.Patients and methodsProspective study (1990–2009) about 84 patients: 44 homozygous sickle cell anemia, one heterozygous sickle cell anemia S/C, 30 thalassemia and nine sickle cell anemia-thalassemia. The mean age was 10.13 years (extremes: 1–45). The red cell units transfused were ABORH1 compatible, then RH-KELL phenotyped after 2006 and phenocompatible after alloimmunisation. The cross-match was realized using indirect antiglobuline test. Irregular red cell antibody screening was realized before every transfusional episode and the direct antiglobuline test was done when there was a poor transfusional efficiency.ResultsThe number of red blood cells units transfused was 3545 (42.2/patient). The number of red cell antibody screening and the number of direct antiglobulin test were respectively 1474 (17.5/patient) and 272 (3.2/patient). Twenty-seven antibodies were identified (32.1%): 14 alloantibodies (16.6%, 16.6% in sickle cell disease, 16.6% in thalassemia, P = 1), 16 antoantibodies (19.04%, 11.1% in sickle cell disease, 33.3% in thalassemia, P = 0.018). There were three cases of association of allo- and autoantibodies. The most frequent alloantibodies were anti-RH3 and anti-KEL1 and were developed after transfusion of standard red cell units. There was no significant relation, neither between sex and risk of immunization, nor between the number of red cell units transfused and alloimmunization. On the other hand, there was a significant relation between autoimmunization and the number of red cell units transfused in thalassemia (P < 0.001).ConclusionThis study proves the interest of using RH-KELL red cell units compatible in patients with hemoglobinopathies in order to reduce alloimmunisation rates.     

Detection of occult blood in stools: comparison of three gaiac tests and a latex agglutination test.

The detection of occult blood in the stools is the only simple screening method for colorectal cancer. The aim of this study was to compare the results obtained with the new Hemolex kit (Orion diagnostica, Fumouze France) with those given by three gaiac tests--Hemoccult (Smithkline diagnostics), Hemofec (Boehringer Mannheim) and Hemopreuve (Fumouze) of 165 stools from patients without special diet. Seventy-one patients with at least two positive gaiac tests or a positive Hemolex test underwent colonoscopy followed, if negative, by fibroscopy: 28 had lesions of the lower digestive tract and five of the upper digestive tract. Sensitivity, specificity and negative and positive predictive value were of 70, 98, 91 and 92% respectively for Hemolex; 82, 74, 94 and 44% for Hemoccult; 94, 67, 98 and 42% for Hemopreuve and 91, 73, 97 and 46% for Hemofec. The results obtained in this study confirm the value of the Hemolex test for the detection of human occult blood in the stools whereas the gaiac tests used are influenced by dietary components (unless restricted), explaining their poor positive predictive value. In conclusion, due to their good negative predictive values, the authors recommend that screening for colorectal tumours should be based on the use of two or three gaiac tests which should be confirmed, when positive, by an immunological test for human hemoglobin.     

Sequential testing in the assessment of clinical skills.

PURPOSE: Educators who use standardized-patient-based (SP-based) tests may save resources by using sequential testing. In this approach, students take a short screening test; only those who fail take a second test. This study investigated whether sequential testing increases efficiency with only a minor decrease of validity. METHOD: In 1994-95, first- through fourth-year (Group 1) and sixth-year (Group 2) medical students at the University of Maastricht took SP-based tests. Each test took two days. In a simulation experiment based on the data from those tests, the authors considered the first day as the screening test and the second day as the second test. They investigated efficiency and validity as a function of the cutoff score of the screening test. They developed and evaluated a new method to determine the optimum cutoff score of the screening test, a method based on minimization of the loss represented by the (weighted) numbers of false positives and negatives in the screening test. RESULTS: The negative predictive value (probability that a student would fail the complete test if he or she had failed the screening test) was low (<60%), while the positive predictive value was high (>96%). Accordingly, stringent pass/fail cutoff scores in the screening test (75% for Group 1 and 80% for Group 2) produced optimum results. Using those cutoff values, only 26% and 11% of 'the students would have had to take the complete test to get a "true" score, while only 0.2% and 0.0% of the students who passed the screening test went on to fail the complete test (false positives). CONCLUSIONS: In a sequential SP-based test, the pass/fail cutoff score of the screening test should be stringent. This can considerably reduce testing time (30% to 40%), while keeping the percentage of false positives at an acceptably low level of less than 0.2%. As an alternative to receiver operator characteristic analysis, minimization of the loss function was found to be an appropriate method to determine the optimum cutoff value of the screening test.     

平均红细胞体积和平均红细胞血红蛋白含量筛查妊娠合并轻型地中海贫血的价值

目的探讨平均红细胞体积(MCV)、平均红细胞血红蛋白含量(MCH)检测在筛查妊娠合并轻型地中海贫血(地贫)中的价值。方法 1514例孕妇在首次产前检查时,同时检查外周血MCV、血红蛋白浓度(Hb)、MCH及血红蛋白电泳等指标,依据首次产前检查时血常规及血红蛋白电泳结果分3组:Ⅰ组127例:Hb<100g/L伴血红蛋白电泳异常;Ⅱ组69例:Hb<100g/L而血红蛋白电泳正常;对照组1318例:Hb>100g/L及血红蛋白电泳正常;以基因诊断作为地贫诊断金标准。结果Ⅰ组MCV及MCH最低,明显低于Ⅱ组和对照组(P<0.01),而Ⅱ组与对照组无显著性差异(P>0.05)。MCV及MCH检测筛查地贫与基因诊断结果比较:灵敏度(Se)98.06%、特异度(Sp)72.04%、假阳性率0.28、假阴性率0.02、准确度90.31%、阳性预测值79.53%、阴性预测值90.30%、阳性似然比3.50、阴性似然比0.028。结论轻型地贫者有MCV、MCH降低的特征,临床上检测MCV、MCH筛查妊娠合并轻型地贫,其灵敏度高,且特异度也较高,假阳性率和假阴性率低。方法简便、实用、经济。可作为基层医院轻型地贫的筛查指标。     

Maternal carrier screening with single-gene NIPS provides accurate fetal risk assessments for recessive conditions

PurposeThe purpose of this study was to evaluate the clinical performance of carrier screening for cystic fibrosis, hemoglobinopathies, and spinal muscular atrophy with reflex single-gene noninvasive prenatal screening (sgNIPS), which does not require paternal carrier screening.MethodsAn unselected sample of 9151 pregnant individuals from the general US pregnant population was screened for carrier status, of which 1669 (18.2%) were identified as heterozygous for one or more pathogenic variants and reflexed to sgNIPS. sgNIPS results were compared with newborn outcomes obtained from parent survey responses or provider reports for a cohort of 201 pregnancies.ResultsOverall, 98.7% of pregnant individuals received an informative result (no-call rate = 1.3%), either a negative carrier report or, if identified as heterozygous for a pathogenic variant, a reflex sgNIPS report. In the outcomes cohort, the negative predictive value of sgNIPS was 99.4% (95% CI = 96.0%-99.9%) and average positive predictive value (PPV) of sgNIPS was 48.3% (95% CI = 36.1%-60.1%). Importantly, personalized PPVs accurately reflected the percentage of affected pregnancies in each PPV range, and all pregnancies with a sgNIPS fetal risk of >9 in 10 (90% PPV) were affected.ConclusionAlthough traditional carrier screening is most effective when used to assess reproductive risk before pregnancy, more than 95% of the time it is pursued during a pregnancy and is complicated by incomplete uptake of paternal carrier screening (<50%) and misattributed paternity (～10%). Even in an idealized setting, when both partners have carrier screening, the maximum risk for having an affected pregnancy is 1 in 4 (equivalent of a 25% PPV). Carrier screening with sgNIPS during pregnancy is an alternative that does not require a paternal sample and provides accurate fetal risk in a timely manner that can be used for prenatal counseling and pregnancy management.     

Evaluation of Clinitek in the screening and optimisation of the diagnosis of urinary tract infection

A study was conducted to compare the interest of using Clinitek and leucocytes esterase, blood, nitrites strip Multistix-8 SG (Ames-Bayer Diagnostics) with conventional method (dilution of urine in agar plate) and with automated system (Autobac) as a screening procedure to detect significant bacteriuria. The results are expressed in terms of sensitivity, specificity, predictive value of a negative and positive test. A total of 1303 urine samples were tested of which 730 (56%) were founded negative with Clinitek or conventional urine analysis (Se = 83.6%; VPN = 89.6%). Criteria for urinary tract infection were present for 193 samples (14.8%), the predictive value of a negative test for leucocytes, blood or nitrites (99.6%) justifies the use of Clinitek for economical screening of urine. Overall agreement is higher with the results or Clinitek (in few seconds) than with the Autobac (in 4-5 hours) when compared to the conventional method. The authors propose Clinitek as an effective method for screening and optimised urine analysis for urinary tract infection.     

Serologic confirmation of Neisseria gonorrhoeae by monoclonal antibody-based coagglutination procedures.

Two commercially available monoclonal antibody coagglutination tests, Phadebact Monoclonal GC OMNI Test (PMGOT; Pharmacia Diagnostics AB, Uppsala, Sweden) and GonoGen (GG; New Horizons Diagnostics, Columbia, Md.), for the confirmation of Neisseria gonorrhoeae were evaluated. The sensitivities of PMGOT and GG were 99.2 and 98.7% and the specificities were 91.5 and 100.0%, respectively. False-positive reactions were observed with Neisseria lactamica and Neisseria meningitidis in PMGOT. A modification of the procedure recommended by the manufacturer for PMGOT was done by substituting Todd-Hewitt broth for 0.9% saline to prepare the suspension of the test organism. This eliminated technical difficulties with the test and resulted in a sensitivity and a specificity of 99.3 and 100.0%, respectively. Advantages offered by the modified PMGOT over GG were the better predictive value of the negative test, the lower cost, the ease of reading of the test, and the lack of noninterpretable results.     

Evaluation of laboratory methods for the classification of oxacillin-resistant and oxacillin-susceptible Staphylococcus aureus

The purpose of this study was to examine the efficacy of the oxacillin disk diffusion test and the methicillin and oxacillin agar screen tests as predictors of oxacillin resistance as defined by the reference broth microdilution method. A total of 444 clinical isolates of Staphylococcus aureus collected from individual patients over a four-year period were tested by (1) the oxacillin disk diffusion test, with particular attention to the presence of fine growth of a resistant subpopulation within the zone of inhibition (Ox Grow interpretive criteria); (2) the agar screen method using agar plates with 4% NaCl and either 6 mg/L oxacillin or 10 mg/L methicillin; and (3) the oxacillin and methicillin broth microdilution test methods with 2% NaCl supplementation. Overall, 62 (14%) isolates were resistant and 382 (86%) isolates were susceptible to oxacillin with the use of the reference broth microdilution system. The results indicate that the disk diffusion test with the use of the Ox Grow criteria had a high sensitivity (94%) and negative predictive value (98%) but a low specificity (67%) and positive predictive value (32%) when compared with the reference broth dilution test. Similarly, the agar screen tests had a high sensitivity (95-97%) and negative predictive values (99%) but low specificity (64-74%) and positive predictive values (30-37%). These data indicate that the agar screen tests and the oxacillin disk test with the use of the Ox Grow interpretive criteria may be useful as screening tests for detecting resistance to the penicillinase-resistant penicillins but that all resistant isolates should be confirmed by the reference broth dilution method because of the large number of false-resistant screening test results.     

桂西地区珠蛋白生成障碍性贫血的红细胞参数筛查价值探讨

目的研究红细胞参数在不同类型珠蛋白生成障碍性贫血筛查中的诊断价值,为珠蛋白生成障碍性贫血患者提供敏感度和特异度高而又经济快捷的筛查方法。方法选取经我院基因诊断确诊的不同类型的珠蛋白生成障碍性贫血患者149例,正常对照51例,采用HORIBA ABX PENTRA DX 120全自动血细胞分析仪进行以下红细胞参数测定：血红蛋白（HGB）、红细胞平均体积（MCV）、红细胞平均血红蛋白含量（MCH）、红细胞平均血红蛋白浓度（MCHC）和红细胞分布宽度（RDW）,并进行分析统计。结果地贫各组红细胞参数与正常对照组比较差异均有统计学意义（P〈0.05）。HGB、MCV、MCH、MCHC和RDW筛查α、β和α＋β珠蛋白生成障碍性贫血的灵敏度分别是69.6%、83.3%和72.7%,84.8%、97.9%和100%,88.6%、100%和100%,78.5%、77.1%和77.3%,57.0%、64.6%和63.6%,HGB、MCV、MCH、MCHC、RDW筛查珠蛋白生成障碍性贫血的特异度分别是76.5%、96.1%、70.6%、49.0%和80.4%。结论红细胞参数MCV〈80 fl作为桂西地区珠蛋白生成障碍性贫血的筛查指标是最佳的。     

Comparison of the RPHA and EIA techniques for the detection of HBs antigen among pregnant Thai women

Five hundred serum samples obtained from pregnant women attending an antenatal clinic in Bangkok were tested for HBsAg by reverse passive hemagglutination assay (RPHA) and enzyme immunoassay (EIA). It was found that 21 (4.2%) and 28 (5.6%) of the sera were positive by RPHA and EIA, respectively. The sensitivity and specificity of the RPHA were 75% and 100%, respectively, when using EIA as the standard method. The RPHA positive predictive value was 100% and the negative predictive value was 98.5%. Accuracy was 98.6%. This study showed that the RPHA was simple and required inexpensive equipment, making it suitable for mass screening. However, the possibility of false negative readings due to low levels of HBsAg should be kept in mind, especially in the blood transfusion practice.     

Diagnostic value of a card agglutination test (Testryp CATT) in the mass screening of human trypanosomiasis in the Congo

A field serological study using the Testryp CATT on whole blood was performed during a mass screening of sleeping sickness in a congolese focus (3,530 patients). This test which presented a good specificity (94.8%), revealed on the other hand a low positive predictive value (26.9%). The sensitivity (68.8%) confirms the previous results obtained in Congo. Association of immunoserological tests (CATT and Indirect Immunofluorescent Antibody Test) and clinical diagnosis (examination of lymph nodes) was usefulness for specify an efficient and rapid control of the human reservoir. The improvement of the CATT diagnostic value was discussed.     

Evaluation of the performance of the EIAgen HCV test for detection of hepatitis C virus infection

The EIAgen HCV test (Adaltis Inc., Montreal, Canada) is an enzyme immunoassay (EIA) for the detection of anti-hepatitis C virus (HCV) antibodies. This study compared the performance of this test side-by-side with the current Ortho HCV 3.0 Anti-HCV assay (Ortho-Clinical Diagnostics Inc., Johnson & Johnson Company, Raritan, NY, USA). Among 2559 specimens examined, 178 were true positives, 2376 were true negatives and 5 were indeterminate. The sensitivity of the EIAgen HCV test was 100%, versus 98.3% for the Ortho HCV test, while their respective specificities were 98.1% and 98.2%. The EIAgen HCV test gave a positive predictive value of 79.8% and a negative predictive value of 100%. Overall, the concordance of this test with the Ortho HCV test was 98.2%. Specimens from potentially interfering substances, such as sera from pregnant women, sera from patients with acute non-C hepatitis, autoimmune diseases, lipidemia, or from patients undergoing hemolysis, showed no interference with either EIA. An EIAgen HCV test signal-to-cut-off ratio of >5.9 would be highly predictive of a true-positive finding in these specimens. The EIAgen HCV test is well suited for screening blood and blood products in antibodies to HCV.