全自动生化分析仪上胱抑素C试剂对血清钙测定的影响

目的研究在全自动生化分析仪上胱抑素C试剂对血清钙测定的影响。方法单独测定血清钙,在测定胱抑素C后再测定血清钙,比较两结果的异同;将混合血清用不同浓度的胱抑素C试剂I稀释,测定血清钙浓度,观察试剂I对结果的影响。结果单独测定血清钙浓度是（2．56±0．056）mmol／L,在测定胱抑素c后测得的血清钙浓度是（2．28±0．053）mmol／L,差异有统计学意义（t=22．97≥t0.05．19=2．093,P〈0．05）;混合血清用不同浓度的胱抑素c试剂I稀释后,血清钙检测结果减少的幅度与胱抑素C试剂I的浓度呈直线正相关（r=0．982）。结论胱抑素C试剂对血清钙测定有负干扰,在生化分析仪上检测时应放在不同检测单元中进行。     

昆明地区健康人群血清胱抑素C参考区间调查

目的调查昆明地区健康人群血清胱抑素C（CystatinC,Cys-C）水平,建立实验室诊断参考区间。方法应用颗粒增强免疫透射比浊法测定130例健康受检者血清胱抑素C浓度;用SPSS16．0软件对检测结果进行统计学处理。结果130例健康受检者的血清胱抑素C浓度与性别、体重指数无关。受检者的血清胱抑素c浓度1-60岁年龄段血清胱抑素C的浓度水平一致,95％的可信区间为0．500-1．120mg／L;大于60岁年龄段95％的可信区间0．670-1．290mg／L。结论胱抑素C的参考范围在不同年龄人群中是不一致的,昆明市健康人群1-60岁血清胱抑素C的参考范围是0．500-1．120rag／L;大于60岁年龄段95％的可信区间为0．670-1．290mg／L,因此在临床上评价肾小球滤过率应建立适宜的参考范围。     

晨尿胱抑素C及微量白蛋白联合检测在早期2型糖尿病肾病诊断中的价值

目的：探讨晨尿胱抑素C及微量白蛋白联合检测在早期2型糖尿病肾损伤诊断中的效果及临床意义。方法：随机选取我院收治的50例2型糖尿病肾病患者（研究组）,予以晨尿胱抑素C及微量白蛋白联合检测诊断,另选50例我院健康体检者（对照组）,对比晨尿胱抑素C及微量白蛋白检测指标。结果：对照组晨尿胱抑素C平均水平为（0.11＆#177;0.09）mg/L、微量白蛋白检测平均水平为（12.85＆#177;3.52）mg/L,研究组晨尿胱抑素C平均水平为（1.02＆#177;0.49）mg/L、微量白蛋白检测平均水平为（33.50＆#177;5.25）mg/L,研究组晨尿胱抑素C与微量白蛋白检测结果均明显高于对照组,（P＜0.05）,差异有统计学意义。结论：晨尿胱抑素C及微量白蛋白联合检测可准确反映DN病情,应用两者联合检测可有效提高DN临床诊断准确率和灵敏度,对早期糖尿病肾病的治疗及早期药物干预有重要的临床意义。     

兰州市健康入血清胱抑素C浓度参考范围的调查

目的 调查兰州市健康人血清胱抑素C（Cys C）浓度的参考范围。方法 应用颗粒增强免疫透射比浊法测定115例健康受检者血清胱抑素C浓度；用SPSS11．0软件对检测结果进行统计学处理。结果 15例健康受检者的血清胱抑素C浓度与性别无关。受检者的血清胱抑素C浓度1～50岁年龄段血清胱抑素C的浓度水平一致，95％的可信区间为0．790～1．250mg／L；大于50岁年龄段95％的可信区间为0．660～1．760mg／L。结论 兰州市1～50岁血清胱抑素C的参考范围是0．790～1．250mg／L，大于50岁年龄段的参考范围是0．660～1．760mg／L，与文献报道基本一致。     

自建胱抑素C检测系统分析性能的评价

目的通过应用CLSI EP系列方案分别对一种国产颗粒增强免疫比浊法胱抑素C试剂结合日立7600-020全自动生化分析仪建立的检测系统的分析性能进行评价,了解该检测系统分析性能能否满足临床需要。方法采用EP-5A2、EP-6A对自建检测系统精密度、最低检测限、线性、试剂稳定性等技术指标进行测定。采用EP-9A2与进口检测系统进行方法比对试验。结果自建检测系统批内、批间、天间及总不精密度均低于8%;最低检测限为0.11mg/L;4℃试剂稳定性大于或等于30d;标本胱抑素C水平为0.5~8.0mg/L时,线性良好,偏倚较小;方法比对试验结果Y=0.829 1 X＋0.007 5,r2=0.993 8。结论国产胱抑素C试剂结合日立7600-020生化分析仪检测性能可以满足临床实验室的需要,与进口检测系统比对结果差异无统计学意义（P〉0.05）。     

胱抑素C与尿微量蛋白及尿酶联合检测在不同程度肾病中的应用价值

目的探讨血清胱抑素C（cystatin C，Cys C）、尿微量蛋白与尿酶联合检测对不同程度肾脏损害的临床诊断价值、可行性和监控作用。方法血清胱抑素C采用颗粒增强透射免疫比浊法（PETIA）分析，对30名健康对照者和98名不同病程的肾功能损害者进行尿微量清蛋白（mAlb）、尿转铁蛋白（UTf）、α1-微球蛋白（α1-MG）、β2-微球蛋白（β2-MG）进行检测分析，动态监测法测N-乙酰-β-D-氨基葡萄糖苷酶（NAG），Jaffe速率法测肌酐。结果血清胱抑素C、尿微量蛋白与NAG／Cr测定结果明显高于健康对照组，其差异有统计学意义（P〈0．01）。但肌酐清除率（Ccr）、血尿素（BUN）、血肌酐（Cr）在早期临床无症状组的比较中，无统计学意义（P〉0．05），单项检测时阳性率较低，联合检测时阳性率可明显提高，可达91．83％；血清胱抑素C、尿微量蛋白与尿酶扣肾病的严重程度呈显著正相关。结论尿蛋白定性阴性不能排除肾脏的早期损伤，血清胱抑素C、尿微量蛋白与尿酶联合检测是诊断肾脏早期损伤的灵敏与可靠的实验室指标，它在肾脏损伤程度的分析中有重要的意义。     

探讨血清视黄醇结合蛋白和胱抑素C在肾脏疾病中的诊断价值

目的：探讨血清视黄醇结合蛋白（retinol blinding protein ,RBP）和胱抑素C（Cystatin C ,CysC）联合检测在肾脏疾病中的临床诊断价值。方法采用Beckman‐Coulter全自动生化仪分别检测173例肾病患者和50例健康体检者的血清尿素氮（U‐rea）、肌酐（Cr）、尿酸（UA）、视黄醇结合蛋白（RBP）、胱抑素C（CysC）的含量,并进行相关的统计学分析。结果173例肾病患者的RBP浓度为（70．86±14．41）mg／L ,CysC浓度为（3．41 ± 0．65）mg／L ,对照组RBP浓度为（41．36±5．68）mg／L ,CysC浓度为（0．98 ± 0．20）mg／L ,肾病组明显高于对照组（P＜0．05）。各疾病组 Cysc的检出阳性率最高,RBP次之,二者联合检测阳性率更高,明显高于传统肾功能指标Urea、Cr、UA。结论血清视黄醇结合蛋白和胱抑素C可作为诊断肾脏疾病的敏感指标,二者联合检测可提高诊断阳性率。     

OLYMPUSAU640型全自动生化分析仪性能验证

目的通过选取部分生化项目,对本实验室的OLYMPUSAU640型全自动生化分析仪从精密度、线性范围、正确度、参考区间四个方面进行性能验证．保证其检测结果的准确可靠。方法测定项目包括AST、TP、GGT、GLU、CHOL、P。根据CLSI推荐的EP5-A2文件进行精密度验证;根据EP15-A2文件进行正确度验证;根据EP6-A2文件进行线性范围验证;根据C28-A2文件进行生物参考区间验证。结果批内精密度和批间精密度分别小于1／4CLIA＇88的允许范围和1／3CLIA’88的允许范围;正确度验证实验显示相对偏倚（sE）小于1／2CLIA’88的允许偏倚范围;线性范围验证显示,AST、TP、GGT、GLU、CHOL、P的斜率分别为0．998、0．977、1．007、1．006、0,998、0．982（r≥0．975）,线性范围分别为0-987．5U／L、30．6～122．25g／L、0～1253U／L、0—46．5mmol／L、0～15．14mmol／L、0～6．68mmol／L;参考区间验证显示各项目的现行参考区间有效。结论本实验室OLYMPUSAU640型全自动生化分析仪性能良好。可以满足临床的质量要求。     

新疆地区维吾尔族和汉族血清胱抑素C参考值范围的调查

目的建立新疆维吾尔族和汉族健康人群血清胱抑素C参考值范围。方法采用日立7600-020大型全自动生化分析仪免疫比浊法检测923例维吾尔族和1 256例汉族健康人血清胱抑素C水平。结果新疆地区血清胱抑素C水平参考值范围:1岁的男性维吾尔族和汉族健康人血清胱抑素C水平95%可信区间分别为0.85～0.95、0.85～1.00 mg/L,女性分别为0.82～0.93、0.81～0.95 mg/L;～60岁的男性维吾尔族、汉族健康人血清胱抑素C水平分别为0.78～0.80、0.79～0.82 mg/L,女性分别为0.70～0.73、0.71～0.74 mg/L;60岁的男性维吾尔族、汉族健康人血清胱抑素C水平分别为0.92～0.98、0.92～0.96 mg/L,女性分别为0.85～0.92、0.91～0.96 mg/L。结论 1岁和大于60岁维吾尔族和汉族健康人群中,血清胱抑素C水平无民族和性别的差异(P0.05),而在～60岁健康人群中则性别的差异有统计学意义(P0.05),民族差异无统计学意义(P0.05),且此年龄段的血清胱抑素C水平与其他年龄段差异有统计学意义(P0.05)。     

颗粒增强透射免疫分析法测定血清胱抑素C方法学评价

目的在HITACHI7600-010生化分析仪上采用颗粒增强透射免疫分析(PETIA)法测定血清胱抑素C(CysC),评价其方法的性能指标。方法建立分析参数,评价性能指标。结果血清4℃保存稳定7天,-20℃和-70℃保存至少稳定5周。检测限为0.12mg/L,线性范围:0~8.11mg/L。1.08、1.68、2.78mg/L混合血清批内CV分别为:2.6%、3.9%、1.7%;批间CV分别为:3.9%、4.6%、2.2%;总CV分别为:4.1%、4.7%、2.3%。平均回收率为:96.3%,低(1.26mg/L)、高(4.27mg/l)两个水平质控物测定均值(n=30)在允许误差范围内(靶值±靶值×15%)。Hb<10.8g/L、胆红素≤945μmol/L、TG<12.87mmol/L无干扰。不考虑性别和年龄的参考范围为:0.51~1.27mg/L。结论在生化分析仪上采用PETIA法测定血清CysC具有较好的性能指标,很方便和其他相关项目建立组合试验,更好地评估肾小球滤过率。     

Analytic and clinical validation of a standardized cystatin C particle enhanced turbidimetric assay (PETIA) to estimate glomerular filtration rate

Abstract Background: Cystatin C is an alternative biomarker for assessing glomerular filtration rate (GFR), yet lack of standardization could hinder its widespread use. In this study we analytically and clinically validated a newer cystatin C particle-enhanced turbidimetric assay (PETIA) traceable to a certified reference material and compared it to the more commonly used particle-enhanced nephelometric assay (PENIA). Methods: Samples from four patient cohorts at the Mayo Clinic were studied: 1) clinical convenience samples (n=50); 2) samples from patients undergoing iothalamate urinary clearance testing for clinical indications (n=101); 3) volunteers without kidney disease (n=292); 4) samples from 1999-2000 with previous cystatin C measurements. Results: The cystatin C PETIA was analytically robust between 0.15 mg/L and 8.36 mg/L. PETIA cystatin C values were 27.5% higher than PENIA results. Furthermore, PENIA results were 12.9% lower in 2010 than in 2000. PETIA cystatin C values and existing equations performed reasonably well to estimate GFR with an overall -7.4% bias for all patients analyzed. Age and gender specific reference intervals were established for the PETIA cystatin C. Conclusions: Cystatin C can be precisely measured by PETIA traceable to the international reference material, ERM-DA471/IFCC, using a routine chemistry autoanalyzer. There are important biases between this assay and the widely employed Siemens PENIA. This study highlights the importance of assay standardization if cystatin C is to be widely used to estimate GFR.     

Particle enhanced turbidimetric immunoassay for the determination of urine cystatin C on Cobas c501

ObjectiveUrinary cystatin C has been reported to be a good marker for tubular damage and acute kidney injury. The aim of this study was to develop a high throughput assay for the quantification of urine cystatin C.MethodsAntigen-excess, imprecision, interference, linearity, recovery, sample stability and reference values were evaluated on Cobas c501.ResultsThe assay was linear over the dynamic range of the study (R² = 0.9994). The total assay imprecision was below 5%. The assay recovery was estimated at 87–100%. No tendency to antigen-excess (up to 35 mg/L), nor interference with haemoglobin (1.25–10 g/L) was observed. Cystatin C was stable for 1 day at ambient temperature (19–23 °C) but for 2 days at + 4 °C. The reference interval for cystatin C in urine was < 0.414 mg/L.ConclusionsThe urinary cystatin C assay verified to be a reliable assay with convenient performance characteristics, enabling routine testing on clinical chemistry platforms.     

酶法糖化血红蛋白试剂盒方法学比对评价

目的评估一种酶法测定糖化血红蛋白（HbAlc）试剂盒的性能。方法酶法测定HbAlc,评价的方法学指标为试剂盒的线性范围、不精密度、抗干扰性、回收率,并分别与免疫法和高效液相（HPLC）法进行相关及偏倚分析。结果该试剂盒的检测在4．3-12．9％呈线性;不精密度测定低、中、高值批内及批间CV在0．89％～1．43％之间,总CV在1．77-2．16％;HbAlc标准为5．5％和10．5％其回收率分别为99．0％、102．1％;干扰实验：维生素C〈500mg／L、胆红素〈400mg／L、溶血素〈5000mg／L、乳糜〈2％时,对结果无明显干扰（干扰率（±5％）。酶法HbAlc与免疫法和HPLC法的测定结果比较其回归方程分别是：Y=1．0417X-0．7187和Y=0．9881X-0．0944,相关系数均为r=0．99,P〈0．05,检验方法之间具有显著的统计学意义,经验证酶法测定HbAlc与免疫法和高效液相法的偏倚都在允许范围内。结论酶法HbAlc试剂盒在不精密度、抗干扰性、线性范围均符合临床要求,与常规方法比较相关良好偏差较小,可完全满足临床对HbAlc检测需求。     

血浆总同型半胱氨酸检测系统的方法学评价和量值溯源

目的:评价自建血浆总同型半胱氨酸(total homocysteine,tHcy)开放系统的分析性能,探讨量值溯源的临床实际应用。方法:应用美国临床和实验室标准化协会系列文件,对AXIS-SHIELD公司tHcy试剂盒进行方法学评价,包括不精密度、分析测量范围、不准确度、抗干扰性及参考区间的验证。结果:tHcy在浓度为15.5μmol/L时,总不精密度为2.94%;分析测量范围为4.5~40.4μmol/L;相关结果与雅培公司Axsym免疫分析系统的结果显著相关(r=0.988,P     

Validation of a new standardized cystatin C turbidimetric assay: Evaluation of the three novel CKD-EPI equations in hypertensive patients

Objectives

Analytical and clinical performances of the new standardized cystatin C particle-enhanced turbidimetric immunoassay (PETIA) using DiaSys reagents on Olympus AU2700® analyzer were evaluated.

Design and methods

We have studied imprecision, linearity, limit of detection and limit of quantification of this new immunoassay. Method comparison was assessed in relation to results generated by the standardized Siemens-particle-enhanced nephelometric immunoassay (PENIA). In order to evaluate the clinical relevance of this assay, estimated glomerular filtration rate (GFR) was calculated using MDRD, CKD-EPI creatinine, CKD-EPI cystatin C 2012 and CKD-EPI creatinine–cystatin C 2012 equations and compared to GFR measured using urinary clearance of ^99mTc-DTPA in 100 hypertensive patients.

Results

Cystatin C measurements using DiaSys reagents have reliable analytical performances and are comparable to the standardized Siemens-PENIA method (bias of 0.01 mg/L). The mean measured GFR was 90.0 ± 29.7 mL/min/1.73 m². Bias and accuracy of the three CKD-EPI equations were better than the MDRD. Both CKD-EPI creatinine-based and cystatin C-based formulae had similar bias, precision and accuracy. The combined creatinine–cystatin C equation was significantly more accurate and precise than the CKD-EPI creatinine equation in patients with GFR above 60 mL/min/1.73 m².

Conclusions

The use of cystatin C in a combined equation with creatinine could improve the accuracy of eGFR in the reference interval.     

Performance evaluation of the Roche Tina-quant Cystatin C assay and reference interval for cystatin C in healthy blood donors

Abstract

Objective. To evaluate the performance of the Roche Diagnostics Tina-quant Cystatin C particle enhanced immuno turbidimetric assay for the measurement of plasma and serum cystatin C, and to establish reference intervals for cystatin C in healthy blood donors. Methods and materials. The cystatin C measurements were performed on the Roche Modular Analytics P automated clinical chemistry analyzer. Results. The cystatin C assay was linear in the measuring range 0.40–7.00 mg/L. Within-run CVs ≤ 2.0%, between-run CVs ≤ 4.2%, and total CVs ≤ 5.5% in plasma pools and in commercial cystatin C control materials (range 1.0–4.7 mg/L). Recovery was 99.4–109.3%. No interference was detected from haemoglobin < 0.9 mmol/L, bilirubin < 330 μmol/L and Intralipid® < 20 g/L. Measurement of cystatin C in Li-heparin plasma did not differ significantly from cystatin C measured in serum. Forty patient samples run on the Modular Analytics P (y) were compared to the Siemens Cystatin C assay on the BN II (x): y = 0.817x + 0.270, Sy.x = 0.168 (Deming regression). The non-parametric reference interval for cystatin C was calculated to be 0.41–0.91 mg/L in females (n = 86), and 0.43–0.94 mg/L in males (n = 76). The Mann-Whitney U test showed a significant difference between the two genders (p = 0.015), but the difference was without clinical relevance. A common reference interval for both genders (n = 162) was calculated to be 0.41–0.92 mg/L. Conclusion. The performance of the Tina-quant Cystatin C assay was acceptable for clinical use.     

两种检测方法测定C反应蛋白的比较

目的评估速率散射比浊法和免疫透射比浊法检测C反应蛋白(CRP)的分析性能。方法分别采用速率散射比浊法(美国Siemens Healthcare Diagnostica公司BN-Ⅱ特定蛋白仪)和免疫透射比浊法(芬兰OrionDiagnostica公司CRP快速检测仪)对CRP进行测定,方法学评价指标为精密度、线性范围、抗干扰性、相关性及偏倚。结果 CRP浓度为2.0～80.0 mg/L时,BN-Ⅱ特定蛋白仪总变异系数(CV)<6%;CRP浓度为8.0～80.0 mg/L时,CRP快速检测仪总CV<7%;检测线性范围为8.0～70.0 mg/L。血红蛋白(Hb)<10 g/L、胆红素(Bil)<300 mg/L对2种方法检测干扰<10%,在可接受范围内。甘油三酯(TG)<20 mmoL/L时BN-Ⅱ特定蛋白仪不受影响(干扰<10%)。CRP快速检测仪在TG>15 mmol/L时低值血清干扰>10%,高值血清不受干扰。50份血样相关分析的结果显示2台仪器测定结果的相关性良好(r=0.98,P<0.01)。线性回归分析经Cusum检验显示2台仪器间偏倚差异无统计学意义(P>0.05),BN-Ⅱ特定蛋白仪测定结果较CRP快速检测仪结果偏低,Bland-Altman曲线显示2种方法的平均偏倚为-2.1。结论速率散射比浊法和免疫透射比浊法的精密度、抗干扰性、线性范围符合要求。虽然系统间测定结果存在一定偏倚,但也符合临床检测要求。     

ELISA测定血清半胱氨酸蛋白酶抑制剂C

目的建立ELISA方法测定血清半胱氨酸蛋白酶抑制剂C。方法以双抗体夹心ELISA方法测定血清半胱氨酸蛋白酶抑制剂C。结果该方法的线性范围可达100mg／L。参考值范围为：男,1．81±0．73mg／L。女,1．72±0．69mg／L。回收率为：99．1±3．1％。批内和批间分别为：5．8±0．5％、7．3±O．7％。结论该方法操作简便,快速,准确,适于临床常规应用。