Comparison of chemiluminescence enzyme immunoassay based on magnetic microparticles with traditional colorimetric ELISA for the detection of serum α-fetoprotein

A chemiluminescence enzyme immunoassay based on magnetic microparticles (MmPs-CLEIA) was developed to evaluate serum a-fetoprotein (AFP) in parallel with traditional colorimetric enzyme-linked immunosorbent assay (ELISA).A systematic comparison between the MmPs-CLEIA and colorimetric ELISA concluded that the MPs-CLEIA exhibited fewer dosages of immunoreagents,less total assay time,and better linearity,recovery,precision,sensitivity and validity.AFP was detected in forty human serum samples by the proposed MPs-CLEIA and ELISA,and the results were compared with commercial electrochemiluminescence immunoassay (ECLIA) kit.The correlation coefficient between MPs-CLEIA and ELISA was obtained with R 2 0.6703;however,the correlation between MPs-CLEIA and ECLIA (R 2 0.9582) was obviously better than that between colorimetric ELISA and ECLIA (R 2 0.6866).

Rapid and Sensitive Chemiluminescent Enzyme Immunoassay for the Determination of Neomycin Residues in Milk

Immunoassays greatly contribute to veterinary drug residue analysis. However, there are few reports on detecting neomycin residues by immunoassay. Here, a rapid and sensitive chemiluminescent enzyme immunoassay （CLIEA） was successfully developed for neomycin residue analysis. CLIEA demonstrated good cross-reactivity for neomycin, and the IC50 value was 2.4 ng/mL in buffer.

Electrochemical Determination of Cortisol by Capillary Electrophoretic Enzyme Immunoassay

An electrochemical method for detection of cortisol based on capillary electrophoretic enzyme immunoassay has been developed. A limit of detection of 1.7?0-9 mol/L was obtained.

Determination of Thyroxine with Capillary Electrophoretic Enzyme Immunoassay

A Capillary electrophortic enzyme linked immunoassay with electrochemical detection (CE-EIA-ED) has been developed. The method can be used to determine thyroxine with a limit of 3.8×10-9 mol/L.

Hepatitis C virus antigens enzyme immunoassay for one-step diagnosis of hepatitis C virus coinfection in human immunodeficiency virus infected individuals

BACKGROUND Current diagnosis of hepatitis C virus(HCV)infection requires two sequential steps:testing for anti-HCV followed by HCV RNA PCR to confirm viremia.We have developed a highly sensitive and specific HCV-antigens enzyme immunoassay(HCV-Ags EIA)for one-step diagnosis of viremic HCV infection.AIM To assess the clinical application of the HCV-Ags EIA in one-step diagnosis of viremic HCV infection in human immunodeficiency virus(HIV)-coinfected individuals.METHODS The study blindly tested HCV-Ags EIA for its performance in one-step diagnosing viremic HCV infection in 147 sera:10 without HCV or HIV infection;54 with viremic HCV monoinfection;38 with viremic HCV/HIV coinfection;and 45 with viremic HCV and non-viremic HIV coinfection.RESULTS Upon decoding,it was 100%accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR test.In five sera with HCV infection,HCV RNA was as low as 50-59 IU/mL,and four out of five tested positive for HCV-Ags EIA.Likewise,it was also 100%accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR in 83 sera with HCV and HIV coinfection,regardless if HIV infection was active or not.CONCLUSION The modified HCV-Ags EIA has a lower detection limit equivalent to serum HCV RNA levels of approximately 100 IU/mL.It is highly sensitive and specific in the setting of HIV coinfection,regardless of HIV infection status and CD4 count.These data support the clinical application of the HCV-Ags EIA in one-step diagnosis of HCV infection in HIV-infected individuals.

Study on Shigella Detection by ATP Bioluminescence Magnetic Enzyme Immunoassay

[Objective] The research aimed to establish a rapid detection method for Shigella. [Method] Combining immunomagnetic separation technology with ATP bioluminescence technology, a new kind of fast and accurate ATP bioluminescence magnetic enzyme immunoassay technique for Shigella was established. [Result] Using ATP bioluminescence magnetic enzyme immunoassay technique to detect standard solution for Shigella （ATCC 25931 ）, result showed that correlation coefficient between relative light intensity detected by instrument and bacteria concentration detec- ted by culture counting method was 0.981 1. Moreover, relation curve between relative light intensity and Shigella concentration was drawn. [ Conclusion] The method had a high detection speed and accuracy, and could be used for the rapid detection of pathogen in food and environment.

The clinical value of enzyme-multiplied immunoassay technique monitoring the plasma concentrations of cyclosporine A after renal transplantation

The feasibility and the clinical value of the enzyme-multiplied immunoassay technique （EMIT） monitoring of blood concentrations of cyclosporine A （CsA） in patients treated with CsA were investigated after kidney transplantation. The validation method was performed to the EMIT determination of CsA blood concentration, the CsA whole blood trough concentrations （Co） of patients in different time periods after renal transplantation were monitored, and combined with the clinical complications, the statistical results were analyzed and compared. EMIT was precise, accurate and stable, also with a high quality control. The mean postoperative blood concentration of CsA was as follows： 〈1 month, （281.4± 57.9）ng/mL; 2 - 3 months, （264.5 ± 41.2） ng/mL; 4 - 5 months, （236.4 ± 38.9） ng/mL; 6 - 12 months, （206.5± 32.6）ng/mL; 〉12 months, （185.6± 28.1）ng/mL. The toxic reaction rate of CsA blood concentration within the recommended therapeutic concentration was 14.1%, significantly lower than that of the none-recommended dose group （37.2%） （P〈0.05）; the transplantation rejection rate was 4.4%, significantly lower than that of the none- recommended dose group （22.5%） （P〈0.05）. Using EMIT to monitor the blood concentration of CsA as the routine laboratory method is feasible, and is able to reduce the CsA toxicity and rejection significantly, leading to achieving the desired therapeutic effect.

A New Voltammetric Enzyme Immunoassay System for the Detection of Alkaline Phosphatase

A new voltammetric enzyme immunoassay system was investigated based on p-nitrophenyl phosphate (PNPP) as the substrate for alkaline phosphatase (ALP). PNPP is enzymatically hydrolyzed and the product p-nitrophenol (PNP) is detected by differential pulse voltammetry (DPV), which can be oxidized at +1.02 V (vs. Ag/AgCl) on bare glass carbon electrode (GCE). The conditions for enzymatic reaction and electrochemical detection were studied. According to this method, ALP can be detected with a detection limit of 2.8102 mU/L and a linear range of 4.0102 ~ 1.0106 mU/L.

Electrochemical Enzyme Immunoassay of Tumor Marker CA15-3 with Capillary Electrophoresis

Tumor marker CA15-3 was determined by using capillary electrophoretic enzyme immunoassay with electrochemical detection (CE-EIA-ED). The method can be used to detect CA15-3 with a limit of 0.024 U/mL.

Determination of Progesterone Receptor by Chemiluminescent Enzyme Immunoassay

A new method of chemiluminescent enzyme immunoassay (CLEIA) was developed and the standard curve and regression equation for determination of progesterone receptor (PR) made. The luminosity of tissue samples was tested and PR level was calculated by the regression equation. Correlation analysis revealed that there was a linear relationship between different concentrations of the standard PR samples and the corresponding values of luminosity: Y=3748+463.77X, γ=0 9958. The values of the luminosity in 38 cases of tumor tissues were determined with the highest being 267.32 fmol/mg, the lowest 3.69 fmol/mg and the mean 78.53 fmol/mg. The new method of CLEIA was a stable, creditable,specific and sensitive assay for determination of PR.

DETECTION OF HELICOBACTER PYLORI STOOL ANTIGEN BY NON-INVASIVE ENZYME IMMUNOASSAY

Objective.To evaluate the clinical utility of a new non-invasive enzyme immunoassay(EIA)for the diagnosis of Helicobacter pylori(H.pylori)infection.Methods.Stool specimens of63patients were collected and tested by using a commercial kit for detecting Helicobacter pylori stool antigen(HpSA),of which61patients also underwent 13 C-Urea breath test( 13 C-UBT).The tissue samples of31patients were obtained endoscopically and were examined with histologic technique(Warthin-Starry silver stain).Regarded 13 C-UBT as a golden standard,HpSA test and histologic techniques were evaluated.Using this method,we also investigated the positive rate of H.pylori infection in children in Beijing.Results.The sensitivity and specificity of HpSA test were94.7%and95.1%respectively;the posi-tive and negative predictive values were97.3%and91.7%respectively;and the accuracy was95.1%.The results showed the prevalence of H.pylori infection was26.0%in children(3～18years)of district of Xicheng in Beijing.After treatment ,HpSA seems to disappear rapidly(3～5days)from the feces.Conclusion.The detection of HpSA in stool samples by HpSA test is a rapid noninvasive test for detecting H.pylori infection,and has both high sensitivity and high specificity.It is suitable for screening and diagnosis of H.pylori infection,monitoring the treatment efficacy in routine in all hospitals.

HOMOGENEOUS ENZYME IMMUNOASSAY OF SERUM AFP BY FLUORIMETRIC KINETIC METHOD

The activity of the Ab-bound enzyme(HRP)changed after immunochemical reaction,and can be indicated by a sensitive fluorimetric kinetic method.The finding set the stage for developing sensitive homogeneous immunoassay.AFP was measured as an example.

A NOVEL POLYMER ENZYME LINKED IMMUNOASSAY METHOD AND ITS APPLICATIONS

During the course of study, we found that both poly (N-isopropylacrylamide ) (PNIP) and PNIP-Ab (enzyme-labelled antibody)could be adhere tightly to a cellulose acetale-nitrate membrane, and that the retention of PNIP-Ab on the membrane increased over 30-fold when compared with the unconjugated Ab.Thus we used this characteristic to develop a novel immunoassay method-polymer enzyme linked immunoassay method: homogeneous antigen-antibody reaction and heterogeneous separation process. When applied for detection of human serum HBsAg, this immunoassay system can detect as little as 1 ng/ml of human serum HBsAg.

Fast Diagnosis of Gonorrhea With Enhanced Luminescence Enzyme Immunoassay

Objective:To evaluate the value of enhanced luminescence enzyme immunoassay in the diagnosis of Neisseria gonorrhea(NG) infection. Methods: Anti-catalase antibody for Neisseria gonorrheae combined with enhanced luminescence enzyme immunoassay were used to test for N. gonorrhea. Results: A minimum of 1×10^4/CFU of GC in genital tract secretions or urine could be detected with the technique of luminescence enzyme immunoassay. Conclusion : The enhanced luminescence enzyme immunoassay has the advantage of high sensitivity and specificity for diagnosing NG from genitourinary tract secretion and urine.

Development of Highly Specific Enzyme Immunoassay for Monitoring Serum Digitoxin Level in Patients

We previously developed radioimmunoassays (RIAs) for digitoxin and digoxin using antisera raised against digitoxin 3’-hemisuccinate-bovine serum albumin and digoxin 3’-hemisuccinate-bovine serum albumin conjugates, respectively. Very recently, we converted the RIA for digoxin to an enzyme immunoassay (EIA) system. Here, we aimed to convert the RIA for digitoxin to an EIA suitable for measuring serum digitoxin level in patients, using digitoxin 3’-hemisuccinate-β-D-galactosidase as an enzyme-labeled antigen. The developed EIA showed a quantification range of 1 to 70 ng/mL and exhibited high specificity for digitoxin, with low cross-reactivity to digitoxin metabolites. Compared with a commercial anti-digitoxin antiserum clinically used to monitor serum digitoxin level in patients, our antiserum showed much higher specificity for intact digitoxin. Intra- and inter-assay variations were less than 10.0% and 8.5%, respectively. Recovery was within the range of 93.7% - 107.5%. Mean digitoxin concentrations measured in serum samples (n = 26) from digitoxin-treated patients by EIA using our new antiserum and the commercial anti-digitoxin antiserum were 11.0 and 13.8 ng/mL, respectively. The present EIA, which is superior to RIA in terms of convenience and disposal of waste materials, is expected to be practically useful for clinical monitoring of intact digitoxin in serum.

基于纳米抗体-荧光素酶的黄曲霉毒素B1检测方法构建

黄曲霉毒素B1(AFB1)是一种剧毒、致癌的食源性污染物,严重威胁食品安全和公共健康。为开发快速检测AFB1的生物发光酶联免疫分析(BLEIA)方法,系统测试了3种抗AFB1特异性纳米抗体(NB)与纳米荧光素酶(Nluc)融合蛋白(G8-Nluc、Nluc-NB26和Nluc-NB28)的可溶性表达、纯化情况及酶催化活性。基于3种融合蛋白分别建立BLEIA检测体系,选择Nluc-NB26用于谷物样品的分析和验证。结果表明,Nluc-NB26的可溶性表达量最高,稳定性更好,Nluc-NB28的可溶性表达量次之,而G8-Nluc基本不可溶。不同表面活性剂对G8-Nluc的促溶解性研究表明,添加N-月桂酰肌氨酸钠可显著提高其溶解度,纯化得到的3种融合蛋白均具有良好的酶活性及抗原结合活性。基于融合蛋白的BLEIA检测结果显示,Nluc-NB28-BLEIA、G8-Nluc-BLEIA和Nluc-NB26-BLEIA体系检测AFB1的IC_(50)值分别为4.213,1.697,2.169 ng/mL,表明G8-Nluc-BLEIA体系的灵敏度最高,Nluc-NB26-BLEIA与前者接近,Nluc-NB28-BLEIA最低。综合考虑融合蛋白的可溶性表达量、稳定性及检测性能,对Nluc-NB26-BLEIA开展实际样品的分析和验证,结果表明:这一方法检测谷物中AFB1的平均回收率在91.1%~104.1%之间,与商业化酶联免疫吸附测定试剂盒结果相似,而检测的时间和试剂成本明显降低。研究结果为开发快速、高灵敏的AFB1检测技术提供参考。

利用EIA生物测试法快速定量筛选环境样品中的二噁污染物

将采集的环境样品分作 3份 ,1份用于高分辨色质联用多离子检测测定二的毒性当量浓度 TEQ,另 2份分别用 7-乙氧基 -异吩唑酮 -脱乙基酶 ( EROD)活力诱导法和酶免疫法 ( Enzyme Immuno Assay,EIA)进行生物测试 .结果表明 EIA和EROD这 2种生物试验方法均具有较好的准确性和很宽的线性范围 .比较 Micro- EROD分析结果与化学分析结果以及 EIA分析结果与化学分析结果 ,发现 Micro- EROD生物试验所测得的 TEQ值均高于化学分析法的 TEQ值 .其比值 1 .83～ 3.0 6,平均比值 2 .54± 0 .59.而 EIA所测得的 TEQ值与化学结果的比率 0 .5～ 1 .4,平均比率为 0 .83± 0 .40 .显然由 EIA所测得的 TEQ的平均值比由 Micro- EROD所测得的结果更接近化学分析结果 .因此 EIA法更适合于对环境样品中二类化合物进行快速定量筛选 .

MEIA法测定乙肝病毒表面抗原的评价及临床应用

目的 对微粒子酶免疫测定法(MEIA法)检测乙肝病毒表面抗原进行方法学评价并研究低含量乙肝表面抗原人群阳性检出率。方法 采用美国雅培公司的AXSYM型化学发光仪对乙肝病毒表面抗原卫生部质控物、高浓度乙肝病毒表面抗原标本进行稀释测定,同时与ELISA法检测乙肝表面抗原进行比较;对低浓度(HBsAg≤1μg/L)的标本进行中和确证试验与采用PCR-ELISA法定量测定HBV DNA。结果 微粒子化学发光法检测乙肝病毒表面抗原具有较高灵敏度,达0.1μg/L;有较好的重复性和特异性;低浓度(HBsAg≤1μg/L)在人群中分布率为0.53％。结论 微粒子酶免疫法对提高低含量乙肝表面抗原阳性检出率具有重要意义。

CMIA、FPIA、MEIA与EMIT测定血药浓度的比较分析

目的:分析比较化学发光微粒子免疫分析法(CMIA)、荧光偏振免疫分析法(FPIA)、微粒子捕捉免疫分析法(MEIA)和酶扩大免疫分析法(EMIT)测定血清丙戊酸(VPA)、全血环孢霉素A(Cs A)、血清卡马西平(CBZ)和血清地高辛(DIG)浓度的一致性。方法:通过测定高、中、低浓度质控样品,评价各方法的准确度及精密度,并对临床患者的VPA、Cs A、CBZ和DIG样本进行测定,比较4种方法测定结果的相关性。结果:CMIA与EMIT(测定值为函数Y)比较,测定VPA的结果具有良好的相关性和差异性,YEMIT=1.172XCMIA+0.227(r=0.97),EMIT的测定结果比CMIA平均高17.49%。FPIA与EMIT比较,测定结果具有良好的相关性:VPA,YEMIT=1.259XFPIA-4.671(r=0.97);Cs A,YEMIT=0.832XFPIA+17.63(r=0.97);CBZ,YEMIT=1.156XFPIA-2.657(r=0.98);MEIA与EMIT比较,测定结果有相关性:DIG,YEMIT=0.634XMEIA+0.018(r=0.91);其中Cs A的EMIT测定结果比FPIA平均低2.08%,DIG的EMIT测定结果比MEIA平均低35.91%,而VPA的EMIT测定结果比FPIA平均高16.83%、CBZ的EMIT测定结果比FPIA平均高3.07%。结论:CMIA测定VPA血药浓度、FPIA测定VPA、Cs A、CBZ及MEIA测定DIG血药浓度与EMIT的测定结果,存在差异性(P<0.05),临床应用中应予以关注并作相应调整。

HPLC-MS/MS法与MEIA法在监测器官移植患者他克莫司全血浓度中的比较

目的:比较HPLC-MS/MS法与MEIA法在监测器官移植患者他克莫司全血浓度中的应用。方法:建立和确证可行的HPLC-MS/MS法,并与ME-IA法分别测定他克莫司相同样本的浓度,对测试结果进行统计分析,评价两种方法。结果:HPLC-MS/MS法测定他克莫司平均浓度为(4.86±0.46)ng/mL,MEIA法测定浓度平均为(5.52±0.43)ng/mL,两种方法测定结果相关系数r平均为0.8771,两种方法相关性较强。LC-MS/MS法测定浓度值/MEIA法测定浓度值平均值为(90.3±5.3)%。结论:HPLC-MS/MS法测定浓度为他物在体内的准确浓度,更适用于日常治疗药物监测(TDM)工作。