艰难梭菌腹泻及实验室诊断

目的探讨艰难梭菌A&B毒素测定在临床应用价值,分析艰难梭菌毒素感染的临床特点。方法对四川大学华西医院2011-02/08收集的155份住院腹泻患者大便标本,采用VIDAS艰难梭菌A&B毒素检测试剂盒进行毒素检测。根据A&B毒素检测结果,将研究对象分为3组:艰难梭菌毒素检测阳性(CDAB阳性)组、艰难梭菌毒素检测灰区组和艰难梭菌毒素检测阴性组。对3组的实验室检测数据和临床资料进行分析比较,实验数据包括大便常规、血常规、生化检测以及粪便镜下微生物学检查,临床资料包括患者的年龄性别、使用抗生素与预后情况等。结果共检测了155例腹泻患者的大便标本,其中艰难梭菌A&B毒素阳性17例(10.97%),可疑6例(3.87%)。155例腹泻患者分为艰难梭菌毒素阳性、可疑和阴性3组进行实验室检测结果比较分析,大便隐血试验在阳性组和阴性组间有统计学差异(P=0.027)。3组病患的临床资料分析显示,抗真菌药物和质子泵抑制剂的使用可能是引起艰难梭菌感染的危险因素。结论艰难梭菌A&B毒素检测技术成熟并已商品化,该方法快速、简单、特异性高,可以作为艰难梭菌临床感染的辅助诊断指标。大便隐血试验可提示艰难梭菌感染,但不具有特异性。     

两种检测血清癌胚抗原方法的比较

目的：对酶联免疫荧光法（ELFA）检测癌胚抗原的性能进行评价。方法：选取经电化学发光法（ECLIA）测定的467份血清标本,分为病例组和对照组,采用同步盲法测试,分别用酶联免疫荧光法和电化学发光法进行比对实验,并进行统计学处理和分析。结果：评价方法与比对方法等同,评价方法ELFA癌胚抗原的相关系数为0.978。批内实验：质控标本批内CV2.09%～3.06%,标本批内CV3.56%～3.81%;批间实验：质控标本批间CV2.20%～2.71%,标本批间CV2.07%～4.12%,总精密度2.40%～3.96%。结论：ELFA检测性能基本满足临床常规检测需要。     

第四代HIV1/2酶联荧光免疫试验在性病门诊筛查中的应用及评价

目的探讨新的第四代可联合检测P24抗原和抗体的酶联荧光免疫试验(ELFA)技术,在性病门诊中的检测情况,评价该技术在临床上的应用价值。方法对8 495份初次筛查HIV-1/2抗体的检测者血清,采用ELFA和硒标法(金标法,DIGFA)同时进行检测,对其中任何一种方法结果为阳性的血清,送北京市疾病预防控制中心(CDC)做蛋白印迹实验(WB)确证实验。结果 79例ELFA法和DIGFA法均为阳性样本送经WB确认,结果亦为阳性;3例ELFA法检测结果阳性而DIGFA检测阴性的标本,经WB确证结果为2例不确定,1例阴性排除HIV感染。对其中2例不确定者进行定期随访,2个月后1例标本经WB确认为阳性,3月后另1例WB亦转为阳性。5例ELFA法为阴性DIGFA法为阳性的标本,经WB确认结果为4例阴性,1例不确定。该不确定者1月后随访,经WB检测而排除。结论 ELFA法因能尽早检测到刚出现的P24抗原,可以得到独立的精确的抗原抗体数值,特异性及准确性高,可将普通检测方法的窗口期缩短,可广泛应用于早期检测。     

Multicenter evaluation of a new quantitative highly sensitive D-dimer assay, the Hemosil® D-dimer HS 500, in patients with clinically suspected venous thromboembolism

Introduction

D-dimer testing is widely used in conjunction with clinical pretest probability (PTP) for venous thromboembolism (VTE) exclusion. We report on a multicenter evaluation of a new, automated, latex enhanced turbidimetric immunoassay [HemosIL® D-Dimer HS 500, Instrumentation Laboratory (IL)].

Materials and Methods

747 consecutive outpatients with suspected proximal deep vein thrombosis (DVT, n = 401) or pulmonary embolism (PE, n = 346) were evaluated at four university hospitals in a management study with a 3 month follow-up. Samples were tested at each center using the new D-dimer assay on an automated coagulation analyzer [ACL TOP (IL)], with clinical cut-off for VTE at 500 ng/mL (FEU).

Results

The sensitivity and negative predictive value (NPV) were 100% for all PTP subgroups (no false negative results); for both sensitivity and NPV the lower limit of the 95% CI in patients with moderate/low PTP was higher than 95%. The overall specificity was 45.1% (95%CI: 41.1-49.3%). Higher specificity value was recorded in the low PTP subgroup [49.2% (95%CI: 41.7-56.7)]. No significant differences were found between patients suspected of having DVT or PE; sensitivity and NPV were 100%. The reproducibility of the assay was good, being the total CVs% less than 10% for D-dimer concentration near the clinical cut-off.

Conclusions

The new, highly sensitive D-dimer assay proved to be accurate when used for VTE diagnostic work-up in outpatients. Based on 100% sensitivity and NPV and lower limit of the 95% CI higher than 95%, the assay can be used as a stand-alone test in patients with non high PTP.     

Evaluation of a rapid qualitative immuno-chromatography D-dimer assay (Simplify D-dimer) for the exclusion of pulmonary embolism in symptomatic outpatients with a low and intermediate pretest probability. Comparison with two automated quantitative assays

The performance of a rapid qualitative solid-phase immuno-chromatography-based D-dimer assay (Simplify D-dimer) for diagnosing pulmonary embolism (PE) was evaluated in 469 outpatients with a low or intermediate pretest probability. They were referred to the emergency department of a university hospital during a 4-month period. Test results were compared to those of two automated quantitative assays. Simplify D-dimer assay result was positive in all 47 patients in whom the diagnosis of PE was retained and in 219 of the 422 patients without PE (51.2%), leading to a sensitivity of 100% (95%CI, 92.5 to 100%), a specificity of 48.8% (95%CI, 44.0 to 53.6%) and a negative predictive value (NPV) of 100% (95%CI, 98.2 to 100%). These results compared favorably with those of the Vidas D-dimer New assay [sensitivity = 100% (95%CI, 92.5 to 100), specificity = 49.8% (95%CI, 45.0 to 54.6%) and NPV = 100% (95%CI, 98.3 to 100%)] and the STA^®-Liatest^® D-DI assay [sensitivity = 100% (95%CI, 92.5 to 100%), specificity = 48.1% (95%CI, 43.3 to 52.9%) and NPV = 100% (95%CI, 98.2 to 100%)]. The inter-observer (n = 2) variability was very good with 1.7% discordant readings and a kappa coefficient (K) value = 0.97 (95%CI, 0.93 to 1.00). In conclusion, the Simplify D-dimer assay could be a valuable tool for ruling out PE in out-patients but a specific learning course of those having to work with is required in order to minimize the number of ambiguous reading and to overcome the inter-observer variability.     

Pleural ELFA D-dimer assay: a surrogate marker for malignant pleural effusion

Background

Malignant pleural effusion is associated with enhanced fibrinolysis. However, no data are available concerning the precise role of pleural D-dimer assay in pleural effusion. We therefore assessed the role of pleural D-dimer assay in predicting malignant pleural effusion.

Patients and Methods

A prospective laboratory investigation was conducted in a tertiary care teaching hospital. The study included consecutive patients with pleural effusion who presented at the Pulmonary Department between November 2009 and May 2010. Blood and pleural D-dimer levels were measured by Enzyme Linked Fluorescent assay (ELFA). The results were correlated with the clinical, laboratory, and radiological findings, and with the final diagnosis of the pleural fluid.

Results

A total of 103 patients with pleural effusion were included in the study. The Pleural ELFA D-dimer results were found to be positively correlated with pleural etiology of malignancy (p = 0.0001). Pleural etiology was also correlated with pleural LDH, pleural protein, pleural PH, pleural glucose, pleural and blood CRP, but not with ADA. In a binary logistic regression, only the pleural ELFA D-dimer assay was a significant predictor of the malignant pleural effusion (odds ratio 1.007; 95% confidence interval 1.002-1.012; p = 0.007). The area under the receiver operating characteristics curve for malignancy was 0.79. A D-dimer level of 146 mg/ml had a sensitivity of 82% and a specificity of 74%.

Conclusions

We found high D-dimer levels among malignant pleural effusion. D-dimer might be useful as a simple, noninvasive, surrogate marker for malignant pleural effusion.