BNP (B-type natriuretic peptide) and NT-proBNP (N-terminal pro-B-type natriuretic peptide) are peptide hormones secreted by the heart.Recently, many researches have described that BNP and NT-proBNP were useful markers for the diagnosis of heart failure.We should develop these assays correctly on the basis of full understanding of biological characteristics and guide clinical use for them in medical laboratories.

Objective To analyze the performance of a rapid immunofluorescence assay for plasma NT-proBNP. Methods Human plasma NT-proBNP was measured by RAMP in 264 healthy cases and 78 patients with heart failure. The precision, stability, linearity and interference factors of RAMP were evaluated according to the protocold from America CLSI. Meanwhile, the results were compared with those obtained by Elecsys. Results Functional sensitivity of RAMP in 20% CV and 10% CV were 48 ng/L and 57 ng/L respectively. The linear range was 18-8 000 ng/L. NT-proBNP in plasma samples detected by RAMP were stable at room temperature for 24 hours, 4 ℃ for 3 days and - 20 ℃ for 20 days. No influences on results were observed throughout three freeze-thaw cycles. The results measured by RAMP were compared between EDTA-K2 anticoagulant plasma and heparin anticoagulant plasma, which showed that YEDTA-K2 =0. 953 9 Xheparin + 0. 365 2 ( R2 = 0. 982, P < 0. 01, n = 40 ). The results of EDTA-K2 and heparin anticoagulant plasma using RAMP and Elecsys showed no significant difference( P ＞0. 05). Slight hemolysis( Hb 2 g/L)had small effect on the results of PAMP and Elecsys assays and deviations of them were below 5%. However median and heavy hemolysis( Hb 3-4 g/L )obviously influenced the results with deviation were more than 15%. The values measured by RMAP fell from 390 ng/L to 82 ng/L, and those measured by Elecsys method fell from 390 ng/L to 178 ng/L when 3 different concentrations of triacylglycerol were added, the values measured by two methods fell from 7 777 ng/L to 7 741 ng/L when bilirubin ( 16-330 μmol/L) was added. The anti-interference ability of RAMP method was similar to Elecsys. Results detected with two methods in 45 EDTA-K2 anticoagulant plasma samples were analyzed with Passing and Bablok regression.The regression equation was YRAMP = 0. 972 8XElecsys - 0. 035 2 (R2 = 0. 994, P ＞ 0. 05, n = 45 ). When heparin anticoagulant plasma samples increased to 78 samples, Passing and Bablok regression equation showed:YRAMP= 0. 983 2XElecsys - 0. 037 6 ( R2 = 0. 991, P ＞ 0. 05, n = 78 ). NT-proBNP levels in healthy adults were elevated along with age and related to the gender. The median value of female[105(60-120) ng/L] was higher than that of male [59 ( 44-91 ) ng/L, Z = 3. 264, P < 0. 01] significantly. Conclusions RAMP method has good repeatability, outstanding stability, and broad linear range. The results detected by RAMP is consistent with results detected by Elecsys.

Chronic kidney disease (CKD) is a general term for heterogeneous disorders affecting kidney structure and function.It can be detected by routine laboratory tests.Acute kidney injury ( AKI),previously referred to as acute renal failure(ARF), represents a persistent problem in clinical medicine.Despite significant improvements in therapeutics,the mortality and morbidity associated with AKI remain high.A major reason for this is the lack of markers for early diagnosis of AKI.In this paper,we discuss recommendations for AKI and CKD laboratory assessment and management,and future challenges.( Chin J Lab Med,2012,35:773-779)

Chronic kidney disease ( CKD) has become a pandemic.Laboratory assay takes the important role in early diagnosis of CKD.We should develop these assays correctly on the basis of full understanding of CKD and guide clinical use for them in laboratory medicine.

Objective To investigate the stability and comparability of recombinant human muscle creatine kinase isozyme(CK-MM)in different matrix,and to find out a suitable matrix as a reference material for application of CK measurement system.Methods The stability of the recombinant CK-MM was observed by measuring its catalytic activity in self-made matrix,anti-freeze additive matrix,the certified reference material(CRM)matrix and human serum matrix respectively.For understanding the commutability among different measurement system total CK catalytic activity in various concentration of human serum and the catalytic activity of recombinant CK-MM in different matrix specimen were measured with IFCC recommended reference method and routine reagent produced by Roche and Zhongsheng Diagnostic Company respectively.Results The recombinant CK-MM was stable for 25 days in the self-made matrix,23 days in CRM matrix and at least 240 days in antifreeze additive matrix stored at-20 ℃.The recombinant enzyme protein in self-made matrix and CRM matrix was commutable.Low concentrations of recombinant CK-MM in human serum and in anti-freeze additive matrix were also commutable.Conclusion The recombinant CK-MM had good stability and commutability in either self-made matrix or CRM matrix.It might be used as a candidate reference material for the determination of total creatine kinase in serum.

0.5). Conclusions There is an increasing trend of resistin level in healthy volunteers and patients with obesity, diabetes mellitus and hyperthyroidism in order Resistin also was a positive and an inverse correlation with BMI and resistance index respectively. These results support the hypothesis of Steppan that resistin causes insulin resistance and links obesity to diabetes, and that the high level of resistin in hyperthyroidism can help to explain the phenomenon of its insulin resistance.

74 years were associated with increased cardiac events too(HR = 5.40,95%CI:2.16~11.52,P=0.0002).NYHA classification, LVEF, cTnT?cTnI and CK-MB were not independently predictive of cardiac events.Conclusions Measurement of NT-proBNP in patients with CHF can help to identify patients at higher risk for cardiac events .

Objective To investigate the prevalence of dyslipidemia,hyperglycemia,hypertension and metabolic syndrome(MS)and compare the prevalence rate of dysilipidemia obtained in this study with the previous study during 1984--1986.Methods A total of 16 344 adults in Beijing who attended for the medical examinations were recruited in the study.Subjects were asked to complete questionnaires regarding personal health,lifestyle and family health history.The physical examination emphasized measurement of height,weight and blood pressure.Blood samples were collected after an overnight fast and subjected to serum glucose,TC,HDL-C,LDL-C and TG measurements.MS was diagnosed according to Diabetes Society of Chinese Medical Association(CDS)criteria.Results Dyslipidemia occurred in 36.9%(6 034)of subjects.948 hyperglycaemia cases were found.The prevalence rate of high blood glucose was 5.8%. Hypertension occurred in 17.1% of subjects.Obesity/Overweight occurred in 5 252 subjects with the prevalence rate of 32.1%.On the basis of the diagnostic criteria for MS in China.MS occurred in 12.2% of subjects(14.2% for males and 10.0% for females).In both genders,the rate increased along with the increment of age.65.5% participants had at least one of the metabolic disorders.The prevalence of hypercholesterolemia,hypertriglyceridemia,and abnormally low HDL-C were higher than previous analysis during 1984-1986 in all age groups.Conclusions The prevalence of MS in this large occupational population in Beijing was quite high. The prevalence of hypeflipemia had increased considerably over the past 20 years.Balanced nutrition and reasonable consumption should be undertaken to modify these situations.

Objective By investigating precision,linearity and accuracy of 9 commonly urine albumin assay systems (8 of immuno-turbidimetric assays and 1 of immuno-nephlometric assay),and comparing the concordance of measurement results,to elucidate the quality of the existing analytical systems.Methods Referring to Clinical and Laboratory Standards Institute (CLSI) EP15-A2,two mixed urines with U-Alb levels of 20 mg/L and 200 mg/L were made to validate precision; Referring to CLSI EP14-A2,fourty fresh urines were selected to evaluate matrix effect of saline diluted European Reference Materials (ERM) DA 470 and saline diluted urine,also to reflect the variation of measurement results among systems; Referring to EP6-A,saline diluted urines (10 levels) were made to validate linearity; Taking the theoretical concentration of precisely saline-diluted ERM-DA 470 as the target value,accuracy of each assay system was evaluated.Maximal allowable coefficient variation (CV) of ≤ 15％ was taken as the acceptable precision for each assay system,as rccommcnded by International Federation of Clinical Chemistry (IFCC)-and National Kidney Disease Education Program (NKDEP) ; maximum allowable bias of ≤25％ was taken as criteria for accuracy evaluation as used in Proficiency Test (PT) sponsored by College of American Pathologists (CAP).Results At level of micro-albuminuria(20-200 mg/L),all 9 systems total CVs were ≤ 15％ ; No matrix effect or interference were found in saline diluted ERM DA 470 and saline diluted urine.For A,B,E,F,G and I systems,validated linear regions were close to those stated in kit instruction;For C,D and H systems,the lower limits of validated linear region (18.7,3.6 and 12.0 mg/L,respectively) were higher than those stated in kits instruction (0,0.9 and 5.0 mg/L,respectively) ;For B and C systems,the lower limits of validated linear region were close to the upper limits of reference interval stated in kit instruction.When urine albumin was ≤ 12.6 mg/L,A,E,F,G and I systems showed good accuracy,absolute biases at all dilution were below 3 mg/L,D system showed higher positive bias (5.0-14.4 mg/L),B,C and H systems' biases were not evaluated because of high in-batch CV (the CV of B system≥ 18.1％,of C system ≥ 14.5％,of H system ≥ 39.1％); when U-Alb ranged in 25.2-201.0 mg/L,all 8 systems' relative biases were ≤25％,except D systems,which showed an un-acceptable positive bias (15.9％-44.3％).Good concordance among systems' results was present at level of microalbuminuria(20-200 mg/L),with CV among systems ＜ 15％ ;when urine albumin was ＜ 20 mg/L,CV among systems increased as allumin concentration decreased.The main contribution of variation came from B,C and H systems,which lower limits of linearity were relatively high.Conclusions At level of microalbuminuria(20-200 mg/L),except D system,the other 8 systems show good precision and accuracy;at low level of urine albumin(＜20 mg/L,especially ＜ 10 mg/L),precision and accuracy of some systems(B,C and H system) needs to be improved.

Urinary excretion of albumin indicates kidney damage and is recognized as a risk factor for progression of kidney disease and cardiovascular disease,resulting a widespread clinical utilization of urine albumin measurement.Considerable inter-method difference has been reported for urine albumin,there are no available reference materials and no reference measurement procedures for urine albumin.This review discusses the clinical utilization of urine albumin in recent years,the principles of existing measurement systems and difference of results among systems,and the current status of work about reference materials and reference measurement procedures.