Comparison of the effect of gel used in two different serum separator tubes for thyroid function tests

Background

Selection and verification of blood collection tubes is an important preanalytical issue in clinical laboratories. Today, gel tubes are commonly used with many advantages, although they are known to cause interference in immunoassay methods. In this study, we aimed to compare SSTs of two different suppliers (Ayset clot activator & Gel and Becton Dickinson (BD) Vacutainer SST II advance) with reference tubes and evaluate the effect of storage time in terms of commonly used endocrine tests such as thyroid‐stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3).

Methods

Fifty‐five volunteers were included in the study. Samples were taken into three different tubes and analyzed for serum TSH, fT4, and fT3 on Architect ci8200 Immunoassay System. Clinical decision levels were estimated using total allowable error (TEa).

Results

No difference was found between tubes in terms of TSH, fT3, and fT4 levels. From a statistical standpoint, TSH and fT4 levels were no longer stable during 24, 48, and 72 hours storage time periods. However, their variations were not clinically significant.

Conclusion

Ayset clot activator & Gel tubes and BD Vacutainer SST II advance tubes have comparable results with glass tube in terms of TSH, fT3, and fT4 levels on Architect ci8200 Immunoassay Systems. From a clinical standpoint, serum TSH, fT4, and fT3 concentrations may be considered as stable when storing these tubes over 72 hours.

     

丙型肝炎病毒抗体诊断试剂盒专项抽验情况分析及建议

目的：了解丙型肝炎病毒抗体诊断试剂盒（酶联免疫方法）的总体质量状况,为丙型肝炎病毒抗体诊断试剂盒（酶联免疫方法）的质量监测及监督管理提供参考。方法：根据《中国药典》2010年版三部丙型肝炎病毒抗体诊断试剂盒（酶联免疫法）质量标准,对抽取的丙型肝炎病毒抗体诊断试剂盒（酶联免疫方法）进行法定检验;并进行了与同品种进口试剂盒的质量比较等探讨性研究。结果：按《中国药典》2010年版三部标准检验,抽取的96批样品检验结果全部符合规定,从不同厂家、不同环节抽取的样品质量无显著性差异;国产试剂盒和进口试剂盒对不同基因型系列转换血清PHV901（基因型1a）﹑ PHV912（2b/3）的检测结果一致。结论：丙型肝炎病毒抗体诊断试剂盒（酶联免疫法）总体质量良好。     

High frequency ofYersinia antibodies in healthy populations in Finland and Germany

Sera from 94 healthy Finnish and 100 healthy German blood donors were studied forYersinia enterocolitica antibodies by two different techniques, enzyme immunoassay and immunoblotting, to compare the frequency ofYersinia infections in Finnish and German populations. The prevalence ofYersinia antibodies in Finland (19% and 31% by enzyme immunoassay and immunoblotting, respectively) and in Germany (33%, 43%) is relatively high and may indicate many subclinicalYersinia infections in healthy populations. Postinfectious complications, such as reactive arthritis, may follow also such subclinical infection; sensitive serological tests are important in their diagnosis.     

Anti-actin antibodies of IgM and IgG class in chronic liver diseases detected by fluorometric immunoassay*

ABSTRACT— Using a sensitive fluoroimmunoassay, anti-actin antibodies (AA) of the IgM and IgG classes were measured in 240 patients with various chronic liver diseases and in 211 patients with non-hepatic autoimmune muscle, heart, malignant and inflammatory bowel diseases. Thirty-two out of 40 patients (80%) with autoimmune chronic active hepatitis (CAH) had AA only of the IgG class (geom. mean X = 1.78, SEM±0.07) and only three patients (8%) had both IgG and IgM AA, the latter in lower titres. In patients with primary biliary cirrhosis (PBC) and AMA-positive cholestatic CAH, AA of both IgM and IgG classes were equally represented (60% IgG and 64% IgM AA in PBC, 73% IgG and 51% IgM AA in cholestatic CAH) but the titres were very low (geom. mean IgG AA in PBC 1.035, SEM±0.03, in cholestatic CAH 1.18, SEM±0.02). In contrast to autoimmune (lupoid) CAH, AA were rare in HBsAg positive CAH (9/43, 21%) and only present in low titres. However, in six out of 21 patients with anti-HBs and anti-HBc-positive chronic active hepatitis, high AA of IgG class were found, suggesting the autoimmune type of liver disease. In NANB virus-induced chronic liver disease after blood transfusion, AA were only occasionally found (IgG antibodies 1/19, IgM antibodies 3/19) and none were found in the eight patients with sporadic NANB hepatitis. They were also rare in 30 patients with alcoholic liver disease (3/30, 10%). Of 211 patients with non-hepatic disorders, only 13 patients (6%) had AA (geom. mean of positive titres 0.076, SEM±0.01). We conclude therefore that high titre AA of the IgG class are reliable serological markers for the diagnosis of an autoimmune liver disease.     

Development of quantum dot‐based fluorescence lateral flow immunoassay strip for rapid and quantitative detection of serum interleukin‐6

BackgroundInterleukin‐6 (IL‐6) is an inflammatory factor that increases rapidly in response to infectious diseases including sepsis. The aim of this study is to develop a quantum dot (QD)‐based fluorescence lateral flow immunoassay (LFIA) strip that can rapidly and accurately detect IL‐6 levels.MethodsQD‐based LFIA strips were fabricated by conjugating CdSe/ZnS QDs to the IL‐6 antibody. Performance verification and clinical sample analysis were carried out to evaluate the newly developed strip.ResultsQD‐based LFIA strips were successfully fabricated. The test strip''s linear range was 10–4000 pg/ml, with a linear correlation coefficient of R ² ≥ .959. The sensitivity of the test strip was 1.995 pg/ml. The recovery rate was 95.72%–102.63%, indicating satisfying accuracy. The coefficient of variation (CV) of the intra‐assay was 2.148%–3.903%, while the inter‐assay was 2.412%–5.293%, verifying the strip''s high precision. The cross‐reaction rates with various interleukins (IL‐1α, IL‐1β, IL‐2, IL‐4, and IL‐8) and interferon‐γ (IFN‐γ) were all <0.1%. When the strip was placed in a 50°C oven for 1, 2, 3, and 4 weeks, the test results were not significantly altered compared to storage at room temperature. Furthermore, 200 clinical serum samples were analyzed to compare the strip with the Beckman chemiluminescence immunoassay (CLIA) kit, which revealed a high correlation (n = 200, R ² = .9971) for the detection of IL‐6.ConclusionsThe QD‐based test strip can rapidly and quantitatively detect IL‐6 levels, thus meeting the requirement of point‐of‐care test (POCT) and showing excellent clinical prospects.     

Activated,N-substituted acrylamide polymers for antibody coupling: Application to a novel membrane-based immunoassay

A room-temperature-precipitable, activated terpolymer consisting of N-isopropylacrylamide (NIPAAm)/N n-butylacrylamide(nBAAm)/N acryloxysuccinimide(NASI) (LCST = 7-13°C) at a monomer feed ratio of 60:40:2.5, respectively, was prepared and conjugated to an antibody. The conjugate was evaluated in a novel cellulose acetate (CA) membrane-based immunoassay which utilizes the especially strong physical attachment of the polymer to CA to bind and concentrate the polymer attached protein onto the membrane. When compared in the CA membrane immunoassay to the antibody-poly(NIPAAm) conjugate prepared via anhydrous copolymerization of NIPAAm and NASI at the monomer feed ratio of 40 : 1, respectively, the performance of the NIPAAm/nBAAm/NASI terpolymer was superior to that of the NIPAAm/NASI copolymer (LCST = 32°C) when the studies were carried out at room temperature. However, the terpolymer and copolymer gave equivalent performance when the assay mixture was heated to 45°C. These results indicate the importance of the LCST of the polymer component of the Ab-polymer conjugate to its adsorption and binding on the CA membrane.     

HBsAg弱阳性及HBsAg和HBsAb同时阳性的结果分析

目的对ELISA法检测乙肝五项结果中的HBsAg弱阳性结果及乙型肝炎HBsAg和HBsAb同时阳性的结果进行分析。方法从35 280例乙肝五项ELISA法检测结果中筛出HBsAg弱阳性115例,HBsAg和HBsAb双阳性结果95例,对筛出的210例标本再进行电化学发光(ECLIA)定量检测。结果 115例HBsAg弱阳性结果用ECLIA检测,结果一致为90例。符合率为78.3%。HBsAg和HBsAb双阳性结果95例用ECLIA检测,结果一致为11例。符合率为11.6%。结论 ELISA法检测乙肝五项对HBsAg弱阳性及HBsAg和HBsAb双阳性结果要慎重。HBsAg弱阳性结果中以HBsAg、HBeAb、HBcAb阳性和HBsAg、HBcAb阳性标本占大多数。HBsAg和HBsAb同时阳性的结果可靠性差,要慎重发出报告。     

颗粒增强透射比浊法测定胱抑素C方法学评价

目的用颗粒增强透射比浊法(PETIA)测定血清中胱抑素C(CysC)水平,评价该法用于检测血清中CysC水平的可行性。方法用PETIA检测试剂盒在Cobas 8000全自动生化分析仪上测定血清CysC水平,对方法的不精密度、灵敏度、线性范围等进行评价,并与CysC颗粒增强散射比浊法检测结果进行相关性分析,同时对其参考区间进行验证。结果低值样本和高值样本的批内不精密度CV分别为3.67%,1.15%,批间不精密度CV分别为4.08%,1.53%;准确度的测定偏差仅为-1.25%;此试剂盒检测CysC灵敏度为0.07mg/L;CysC浓度在0.2~8.0mg/L范围内检测线性良好;与西门子德灵颗粒增强散射比浊法(PENIA)比较有良好的相关性Y=0.945 8 X+0.048 6,r2=0.991 3,r=0.995 6,40例健康体检者样本的检测值仅有2例在厂家提供的参考区间之外,90%以上的观测值在待验证区间之内。结论颗粒增强透射比浊法用于定量检测人血清CysC水平,具有简便易行、快捷价廉、准确可靠的优点,适用于在日常临床检测中推广应用。