血吸虫抗体（IgG）检测试剂盒（胶体染料法）临床诊断效能

目的评价血吸虫抗体(IgG)检测试剂盒(胶体染料法)对血吸虫病的临床诊断效能。方法采用血吸虫抗体(IgG)检测试剂盒(胶体染料法)对毛蚴孵化法或/和Kato-Katz法阳性(阳性金标准)的血吸虫病人血清371份,无血吸虫感染史、无血吸虫疫水接触史且粪检结果阴性者(阴性金标准)血清761份进行检测,计算试剂盒检测的阳性符合率(灵敏度)、阴性符合率(特异度)、阳性预测值、阴性预测值、阳性似然比和阴性似然比。结果血吸虫抗体(IgG)检测试剂盒(胶体染料法)检测结果与阳性金标准的符合率(灵敏度)为92.7%(95%可信区间为90.1%～95.3%),与阴性金标准的符合率(特异度)为98.7%(95%可信区间为97.9%～99.5%),阳性预测值和阴性预测值分别为97.2%和96.5%,阳性似然比和阴性似然比分别为71.3和0.07。结论血吸虫抗体(IgG)检测试剂盒(胶体染料法)对血吸虫病具有较好的诊断效能,可用于对血吸虫病的辅助诊断。     

ELISA法检测血清包虫IgG抗体试剂盒的应用评价

目的对ELISA(酶联免疫吸附试验)法检测血清包虫IgG抗体试剂盒进行评价,为其应用提供参考。方法收集2012-01-12就诊的1242位可疑包虫病患者的血清标本,采用ELISA检测血清棘球蚴IgG抗体。结果1242例中就诊患者中对包虫感染有明确诊断(确诊或排除包虫病)的有1130例,其中棘球蚴IgG抗体阳性159例(14.07%),棘球蚴IgG抗体阴性971例(85.93%);以临床诊断为标准得到灵敏度87.06%,特异性91.87%,Youden指数为0.78。结论ELISA法检测棘球蚴IgG抗体的灵敏度和特异性较高,可用于包虫病患者的流行病学调查;并结合B超等影像学检查用于临床包虫病的辅助诊断。     

4种ELISA方法检测牛口蹄疫非结构蛋白抗体的ROC评价

目的 比较4种口蹄疫病毒非结构蛋白抗体(FMDV-NSP)ELISA的临床检测效果。方法 以Ceditest^ ELISA试剂盒检测结果为“金标准”,应用4种ELISA方法检测164份牛血清口蹄疫病毒非结构蛋白抗体,通过平行试验比较各检测方法的特异性,敏感性及检出率,然后应用受试者工作特征(ROC)曲线分析,分析各检测方法的Youden指数,并优化最适临界值,再次比较几种检测方法的特异性,敏感性及检出率。结果 口蹄疫病毒非结构蛋白3ABC抗体检测ELISA试剂盒,口蹄疫病毒非结构蛋白抗体单抗阻断ELISA试剂盒,3B合成肽ELISA试剂盒和本实验室建立的8BF-ELISA的敏感性分别为94.2%(80/85),91.9%(78/85),83.7%(71/85),91.9%(78/85);特异性分别为97.4%(77/79),91.0%(72/79),97.4%(77/79),94. 9%(75/79);检出率为95.8%(157/164),91.5%(150/164),90.3%(148/164),93.3%(153/164)。。经X²检验,4种ELISA的检出率之间无显著性差异(P=0.461>0.05)。但3B合成肽ELISA试剂盒的敏感性明显低于其他3种检测方法,不适合大规模临床样本的初筛试验。结论 在优化临界值后的ELISA A,ELISA B和ELISA D的敏感性和特异性都大于90%,同时有着很高的检出率,均可用于大规模临床的样本的初筛试验。     

猪乙脑病毒IgG抗体间接免疫荧光检测方法的建立与初步应用

目的建立检测猪血清中流行性乙型脑炎病毒(JEV)IgG抗体的间接免疫荧光试验(IFA)。方法用乙脑病毒感染C6/36白蚊伊蚊细胞制备抗原片,建立检测猪血清中JEV-IgG抗体的IFA方法,并用于猪乙脑血清流行病学调查。结果成功建立特异的猪JEV-IgG的IFA检测方法,并对50份母猪、55份仔猪和65份屠宰猪的血清进行检测。乙脑血清抗体效价≥1:200的分别为88.00%,10.91%和24.62%。结论建立的IFA方法能较好的用于猪血清乙脑流行病学调查。     

登革重组抗原与登革IgG抗体反应的敏感性和特异性分析

目的对登革重组包膜蛋白(E蛋白)抗原与登革病毒IgG抗体反应的敏感性和特异性进行评估和分析。方法将登革1-4型重组E蛋白抗原包被ELISA反应板,用间接法ELISA检测登革病人及其它血清样本登革病毒IgG抗体。结果重组抗原能检测出登革病人体内IgG抗体水平和变化情况,对2004年中山登革热疫情病人恢复期血清IgG抗体检出率达100%,无一漏检;在曾流行过登革热的疫区,能检出登革病毒IgG抗体阳性血清;重组抗原与乙脑病人血清没有交叉反应;评估结果显示“登革病毒IgG抗体检测试剂”的灵敏度为95·93%,特异度为96·86%。结论登革1-4型重组E蛋白抗原对登革病毒IgG抗体具较高的敏感性和特异性,可作为“登革病毒IgG抗体酶联免疫诊断试剂盒”开发的原材料。     

全血检测特异性抗结核抗体对结核病快速诊断价值的研究

目的了解全血检测特异性抗结核抗体(LAM-IgG)对结核病快速诊断的价值.方法采受试者手指血20μL用金标试剂盒直接检测LAM-IgG.结果 125例涂阳肺结核抗体阳性检出率为92.0%;267例涂阴肺结核抗体阳性检出率为78.3%;94例陈旧性肺结核抗体阳性检出率为 75.5%;36例肺外结核抗体阳性检出率为83.3%;315例非结核抗体阳性检出率为47.6%.本试验灵敏度为82.7%(324/392),特异度为52.4%(165/315).结论全血快速检测抗结核抗体较血清检测更方便,灵敏度高,但特异度较低,不能作为涂阴肺结核的最终诊断,此项检查可作为涂阴肺结核的辅助诊断和结核可疑者的筛选手段以及肺外结核的诊断指标之一.     

西尼罗病毒抗体酶联免疫吸附试验检测方法的评价

目的系统地评价血清西尼罗病毒(West Nile virus,WNV)抗体的酶联免疫吸附试验(ELISA)检测方法,为在人群和宿主动物中进行WNV感染血清流行病学调查提供技术支持。方法利用构建的包膜蛋白重组质粒(pQE-30)表达纯化西尼罗病毒包膜蛋白,以此为抗原进行ELISA检测。在对抗原包被量、酶标抗体浓度、血清稀释度进行优化的基础上,对本方法的灵敏度和特异度进行评价。结果确定最适抗原包被量为0.034μg,酶标抗体工作浓度和血清稀释度分别为1∶4 800和1∶80;批内变异和批间变异分别为6.7%和22.6%;对小鼠WNV抗体阳性血清53份、JEV抗体阳性血清48份和阴性对照血清94份进行检测,灵敏度为86.8%,特异度分别为93.8%和92.6%。结论本研究建立的ELISA方法灵敏、检测抗体特异,结果可重复,是一种有价值的血清学调查方法。     

90例病毒性胃肠炎患者粪便中诺如病毒检出情况分析

目的 了解病毒性胃肠炎患者中诺如病毒感染情况. 方法 收集北京市2007年2月5~17日共计90例病毒性胃肠炎患者的粪便标本,应用逆转录聚合酶链反应法 (RT-PCR) 和酶联免疫吸附试验 (ELISA) 检测粪便中诺如病毒核酸或抗原,并对RT-PCR阳性标本的PCR产物进行克隆测序. 结果 90例病毒性胃肠炎患者的粪便标本中,35例 (38.89%) RT-PCR为诺如病毒核酸阳性,序列分析结果显示,诺如病毒GⅡ型34例 (97.14%),GⅠ型1例 (2.86%);90例中,39例 (43.33%) 为ELISA检测诺如病毒抗原阳性.以RT-PCR检测结果作为金标准进行比较,ELISA的灵敏度和特异度分别为97.14% (34/35) 和90.91% (50/55) . 结论 诺如病毒是病毒性胃肠炎的主要病原,以GⅡ型流行为主.ELISA快速、简便,其灵敏度和特异度较高,可作为诺如病毒感染的初筛试验.     

肺吸虫抗体快速检测试剂盒(金标渗滤法)的研制和应用

目的开发研制简易、快速、经济、准确的肺吸虫病诊断试剂盒。方法以肺吸虫成虫可溶性蛋白为检测用抗原,以胶体金标记羊抗人IgG为探针,采用自行设计的渗滤装置,检测病人血清中肺吸虫特异性IgG抗体;用深圳康百得生物技术有限公司提供的肺吸虫抗体ELISA检测试剂盒作比较。结果用本试剂盒检测90人份肺吸虫病人血清和100人份健康人血清,其敏感性为98.9%(89/90),特异性为100%(100/100),Youden’s指数为0.989。用该试剂盒分别检测25人份血吸虫病和华支睾吸虫病患者血清,交叉反应率为24%(6/25)和4%(1/25);与姜片虫、囊虫、丝虫、肺结核病人血清均未见交叉反应。ELISA检测结果比较,符合率为93.5%,无显著性差异(χ2=0.7949,P>0.05)。结论肺吸虫抗体快速检测试剂盒(金标渗滤法)敏感性高、特异性强,可与ELISA相媲美,且操作更为简便、快速,结果判读容易,不需特殊仪器设备,非常适合临床检验和现场查病。     

上转发光免疫层析法快速检测棘球蚴病患者血清IgG的评价

初步评价上转发光免疫层析(UPT-LF)法快速检测棘球蚴病患者血清IgG的效果,并与酶联免疫吸附试验(ELISA)法检测结果作比较。2017—2018年,从青海省人民医院和青海大学附属医院收集棘球蚴病临床确诊患者血清,同时从各医院体检中心收集健康者血清,以UPT-LF法和ELISA法检测血样中棘球蚴IgG抗体,以临床诊断结果为标准分析两种检测方法检测的灵敏度、特异度、误诊率、总符合率、约登指数等。两种检测结果的比较进行卡方检验。共收集棘球蚴病患者血样104份,其中多房棘球蚴病(AE) 46份,细粒棘球蚴病(CE)58份;非棘球蚴病患者血样165份。UPT-LF、 ELISA法检测104份临床确诊棘球蚴病患者血清的灵敏度分别为94.2%(98/104)、 78.8%(82/104),二者差异有统计学意义(χ~2=11.250, P <0.01),其中检测AE的灵敏度分别为97.8%(45/46)、 89.1%(41/46),检测CE的灵敏度分别为91.4%(53/58)、 70.7%(41/58); UPT-LF、ELISA法检测165份非棘球蚴病患者血清的特异度分别为95.2%(...     

戊型肝炎病毒抗体双抗原夹心法ELISA的建立与初步应用

目的　建立抗戊型肝炎病毒 (HEV)抗体检测的双抗原夹心ELISA(DS -ELISA) ,并应用于多种动物血清的检测。方法　将大肠杆菌表达的一段HEVORF2区重组抗原分别包被微孔板和进行辣根过氧化物酶 (HRP)标记 ,利用 5份阳性血清和 4 0份阴性血清建立双抗原夹心ELISA ;用 4 0 0份义务献血员血清比较双抗原夹心ELISA与间接法IgG抗体ELISA的符合情况 ;用 3只HEV感染猴系列血清比较双抗原夹心ELISA试剂和Genelabs公司HEVIgG试剂 ;用双抗原夹心ELISA试剂检测新疆地区的部分牛、绵羊、山羊、猪血清和上海地区的部分鸡血清中的HEV抗体。结果　建立了检测HEV抗体的双抗原夹心ELISA方法 ,对 4 0 0份义务献血员血清的检测表明其与间接法IgG抗体ELISA试剂的符合情况良好 ,并且有更高的s/co比值 ;与Genelabs公司HEVIgG试剂的比较表明双抗原夹心ELISA试剂的检出更早 ,尤其是持续时间及强度明显优于Genelabs试剂 ;在所检测的各种动物中均发现了HEV抗体 ,其中猪抗体的阳性率最高 ,表明双抗原夹心ELISA试剂可同时用于不同动物的抗HEV抗体检测。结论　利用大肠杆菌表达的HEV重组抗原建立了双抗原夹心法ELISA ,并可同时用于不同动物的抗HEV抗体检测。     

Seroprevalence of dengue in Trinidad using rapid test kits: a cord blood survey

A cross-sectional sero-epidemiological study was conducted to determine the prevalence of dengue in Trinidad. Two commercial rapid test kits, PanBio Dengue Duo IgM and IgG Rapid Strip Test and the Bio-Check Plus Dengue G/M Cassette Test (Brittney) were used. The immunosorbent assay (ELISA) (FOCUS Technologies, California) was used as the control. One hundred and twenty five cord blood samples were collected (46 from Mt. Hope Women's Hospital (MH) and 79 from the San Fernando General Hospital (SF)). All blood samples were tested in accordance with the two rapid kits and ELISA assay manufacturer's instructions. From 125 cord blood samples, the IgG FOCUS ELISA results showed 93.5 and 95% infections at MH and SF, respectively. Whereas the Brittney and PanBio kits showed 10.9 and 5.1%, and 26.1 and 50.6% for MH and SF, respectively. Based on the FOCUS ELISA (control) assays, the combined seroprevalence rate from north and south Trinidad was 94.4%. IgG and IgM sensitivity and specificity levels were higher in the PanBio than Brittney test kits. The high seroprevalence rates observed in Trinidad are discussed to stimulate more research to explain this phenomenon and to prevent the Southeast Asian scenario from developing in the Americas.     

酶联免疫吸附试验检测猪血清的乙型脑炎抗体的评价

本文报告用酶联免疫吸附试验捕获法和间接法分别检测猪血清乙型脑炎IgM和IgG抗体。酶标法测得的IgM和IgG滴度与血凝抑制试验滴度显著相关。但前者可测出70％的IgG型抗体和63.3％的IgM型抗体,而后者仅56.7％阳性。在乙脑流行季节,两种类型的乙脑抗体出现几乎同样快。IgG可持续终身。IgM仅在短期内检测到,当表示猪乙脑新感染。     

Evaluation of two commercially available ELISAs for the diagnosis of Japanese encephalitis applied to field samples

Objective To compare two commercially available kits, Japanese Encephalitis‐Dengue IgM Combo ELISA (Panbio Diagnostics) and JEV‐CheX IgM capture ELISA (XCyton Diagnostics Limited), to a reference standard (Universiti Malaysia Sarawak – Venture Technologies VT ELISA). Methods Samples were obtained from 172/192 children presenting to a site in rural India with acute encephalitis syndrome. Results Using the reference VT ELISA, infection with Japanese encephalitis virus (JEV) was confirmed in 44 (26%) patients, with central nervous system infection confirmed in 27 of these; seven patients were dengue seropositive. Of the 121 remaining patients, 37 (31%) were JEV negative and 84 (69%) were JEV unknown because timing of the last sample tested was <10 day of illness or unknown. For patient classification with XCyton, using cerebrospinal fluid alone (the recommended sample), sensitivity was 77.8% (59.2–89.4) with specificity of 97.3% (90.6–99.2). For Panbio ELISA, using serum alone (the recommended sample), sensitivity was 72.5% (57.2–83.9) with specificity of 97.5% (92.8–99.1). Using all available samples for patient classification, sensitivity and specificity were 63.6% (95% CI: 48.9–76.2) and 98.4% (94.5–99.6), respectively, for XCyton ELISA and 75.0% (59.3–85.4) and 97.7% (93.3–99.2) for Panbio ELISA. Conclusion The two commercially available ELISAs had reasonable sensitivities and excellent specificities for diagnosing JEV.     

Evaluation of three commercially available Japanese encephalitis virus IgM enzyme-linked immunosorbent assays

We evaluated performance of three commercial Japanese encephalitis virus (JEV) IgM antibody capture enzyme-linked immunosorbent assay (MAC ELISA) kits with a panel of serological specimens collected during a surveillance project of acute encephalitis syndrome in India and acute meningitis and encephalitis syndrome in Bangladesh. The serum and cerebral spinal fluid specimens had been referred to the Centers for Disease Control and Prevention (CDC) for confirmatory testing. The CDC results and specimen classifications were considered the reference standard. All three commercial kits had high specificity (95-99.5%), but low sensitivities, ranging from 17-57%, with both serum and cerebrospinal fluid samples. Specific factors contributing to low sensitivity compared with the CDC ELISA could not be determined through further analysis of the limits and dilution end points of IgM detection.     

不同抗囊尾蚴抗体检测试剂盒用于囊尾蚴病血清学诊断效果评价

目的　评价不同厂家生产的4种抗囊尾蚴IgG、IgG4和IgM抗体酶联免疫吸附试验（ELISA）检测试剂盒的诊断效果,为囊尾蚴病流行病学调查和临床检测提供参考。方法　采用A品牌3种抗囊尾蚴抗体（IgG、IgG4和IgM抗体）ELISA检测试剂盒以及B品牌抗囊尾蚴IgG抗体ELISA检测试剂盒,同时检测40份脑囊尾蚴病患者、100份健康人、30份斯氏并殖吸虫病患者、17份细粒棘球蚴病患者和19份皮下或脑裂头蚴病患者血清,比较不同试剂盒检测囊尾蚴病的敏感度、特异度和假阳性率。结果　A品牌抗囊尾蚴IgG、IgG4和IgM抗体ELISA试剂盒以及B品牌抗囊尾蚴IgG抗体ELISA试剂盒检测囊尾蚴病的敏感度分别为95.00%（38/40）、87.50%（35/40）、7.50%（3/40）和75.00%（30/40）,特异度分别为98.00%（98/100）、100.00%（100/100）、100.00%（100/100）和100.00%（100/100）;A品牌抗囊尾蚴IgG抗体ELISA试剂盒检测囊尾蚴病的敏感度高于B品牌（[χ2] = 6.28,P < 0.05）,两者特异度差异无统计学意义（[χ2] = 2.01,P > 0.05）。4种试剂盒检测并殖吸虫病、细粒棘球蚴病、裂头蚴病患者血清总假阳性率分别为37.88%（25/66）、22.73%（15/66）、62.12%（41/66）和15.15%（10/66）（[χ2] = 37.61,P < 0.05）;其中A品牌抗囊尾蚴IgM抗体ELISA试剂盒检测总假阳性率最高（[χ2] = 7.56,P' < 0.008）,A品牌抗囊尾蚴IgG抗体ELISA试剂盒检测总假阳性率高于B品牌（[χ2] = 8.75,P' < 0.008）。4种试剂盒检测并殖吸虫病患者血清假阳性率分别为40.00%（12/30）、16.67%（5/30）、76.67%（23/30）和13.33%（4/30）（[χ2] = 32.88,P < 0.05）,检测裂头蚴病患者血清假阳性率分别为21.05%（4/19）、26.32%（5/19）、73.68%（14/19）和15.79%（3/19）（[χ2] = 19.97,P < 0.05）,均以A品牌抗囊尾蚴IgM抗体ELISA试剂盒检测假阳性率最高（P' 均 < 0.008）。4种试剂盒检测细粒棘球蚴病患者血清假阳性率分别为52.94% （9/17）、29.41%（5/17）、23.53%（4/17）和17.65%（3/17）,差异无统计学意义（[χ2] = 8.24,P > 0.05）。A品牌抗囊尾蚴IgM抗体ELISA试剂盒检测并殖吸虫病、棘球蚴病和裂头蚴病患者血清假阳性率分别为76.67%（23/30）、23.53%（4/17）和73.68%（14/19）（[χ2] = 14.537,P < 0.05）,其中检测棘球蚴病患者血清假阳性率最低（[χ2] = 14.537,P' < 0.014）;其他3种试剂盒检测并殖吸虫病、棘球蚴病和裂头蚴病患者血清假阳性率差异均无统计学意义（P 均> 0.05）。 结论　不同囊尾蚴病免疫学诊断试剂各有优劣;A品牌抗囊尾蚴IgG抗体ELISA试剂盒敏感度较高,但需进一步解决与其他寄生虫病的交叉反应和稳定性问题。     

2种检测人肾综合征出血热IgG抗体ELISA试剂盒的比较

目的 探讨国产与进口人肾综合征出血热(hemorrhagic fever with renal syndrome, HFRS)IgG抗体ELISA检测试剂盒的性能差异. 方法 采用国产和进口ELISA试剂盒分别检测50例HFRS疫苗接种者血清样本中抗人HFRS IgG抗体含量,分析比较2种ELISA试剂盒的一致性、灵敏性、精密度以及方法学等的差异. 结果 2种ELISA试剂盒的精密度良好,批内变异系数均<5%;2种试剂阳性一致率为100%,阴性一致率为20%,相似率为60%;灵敏性检测结果显示,2种ELISA试剂盒的灵敏性差异较大(P<0.05),国产ELISA试剂盒的灵敏度约是进口ELISA试剂盒的5倍. 结论 国产人HFRS IgG抗体ELISA检测试剂盒灵敏性好,进口ELISA试剂盒特异性好,国产和进口ELISA试剂盒的精密度均良好,在实际应用中应根据具体情况合理选用.     

A rapid method for serodiagnosis of Japanese encephalitis using persistently infected C6/J-121 cells

The usefulness of persistently infected C6/36 (C6/J-121) cells with Japanese encephalitis virus (JEV) for a rapid serodiagnostic test was examined with the sera of men, swine and laboratory animals by indirect immunofluorescent antibody (IFA) technique. Detection of specific antibodies was completed within 3 to 5 hours. Nonspecific fluorescence frequently observed in other IFA tests was few. The sensitivity of antibody detection and the serological specificity of IFA (IgG) were similar to those of hemagglutination-inhibition (HI) test. For the detection of IgM antibodies in sera of JE-patients and naturally JEV infected swine, this method was found to be simpler and more sensitive and rapid than the conventional HI test which required 2-ME treatment of the sera.     

A critical evaluation of commercial immunoassays for antineutrophil cytoplasmic antibodies directed against proteinase 3 and myeloperoxidase in Wegener's granulomatosis and microscopic polyangiitis

OBJECTIVE: To evaluate the performance of 11 commercial enzyme-linked immunosorbent assay (ELISA) kits for the detection of antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) and myeloperoxidase (MPO) in patients with Wegener's granulomatosis (WG) and microscopic polyangiitis (MPA). METHODS: Serum samples were taken from 92 patients with a histological and clinical diagnosis of WG (n=50) or MPA (n=42) and from 30 disease controls (systemic lupus erythematosus, n=15; rheumatoid arthritis, n=15) and 30 healthy controls. Each of the sera was tested for the presence of ANCA directed against PR3 and MPO using 11 commercially available direct ELISA kits, our in-house PR3- and MPO-ANCA capture ELISAs, and the indirect immunofluorescence technique (IFT). RESULTS: In tests for WG using PR3-ANCA, the commercial direct ELISA kits differed widely in their sensitivity (from 22 to 70%) and negative predictive value (NPV) (from 43 to 70%), but only moderately in their specificity (from 93 to 100%) and positive predictive value (PPV) (from 93 to 100%). The highest sensitivity (74%) and specificity (100%) for PR3-ANCA were obtained with the in-house capture ELISA. Similar differences and trends were noted for MPO-ANCA assays. Diagnostic sensitivity was more than 60% for four and at least 50% for six of the 11 ELISA kits. The PPV varied from 84 to 100% and the NPV from 58 to 70%. In tests for MPA, the MPO-ANCA ELISA kit designated F and the in-house capture ELISA were best (both had sensitivity 62% and specificity 100%). For both WG and MPA, maximum sensitivity for ANCA was obtained with IFT (80 and 70% respectively). CONCLUSION: Determination of PR3-ANCA and MPO-ANCA with the commercial direct ELISA kits achieved poor sensitivity for both WG and MPA. The in-house PR3 and MPO-ANCA capture ELISAs performed better than the commercial ELISAs, combining higher specificity with similar sensitivity. IFT remains the best method for ANCA detection in both diseases.     

Relative value of commercial kits for ANA testing

AIMS: We have tested the relative performance of 20 commercial ANA test kits along with that of our own laboratory to assess whether one was clearly superior. METHODS: The sera were drawn from 3 pools that had all been pre-tested in our laboratory: patients with definite SLE; patients with non-connective tissue diseases (CTD), but where a positive FANA had been found; and normal blood donors. The tests were used in accordance with the recommendations of the specific supplier but in a routine serology laboratory. RESULTS: Sensitivity and specificity ranged between 38 and 100%. While the negative predictive value of 4 ELISA kits was 100%, and most others were close, the HEp-2 kits were 100% in only 1 case. A positive predictive value of 100% was also seen with 1 kit. CONCLUSION: Some of the tests are clearly better than others, but the choice may differ depending on the clinical needs, e.g. preference for a good positive or negative predictive value. However, the ELISA kits offered better results than the immunofluorescent technique. Two of them had sensitivity/specificity of > 90%.