Study on performance specifications of 34 routine chemistry analytes in China / 中华检验医学杂志

Objective:The allowable total error ( TEa),allowable imprecision ( CV)and allowable bias( Bias)were recommended for 34 routine chemistry analytes in China. Methods:According to the performance specification setting mode newly determined at the Milan conference in Italy,the performance specification was derived based on components biological variation (BV)and current state of the art mode. The data(including EQA data and IQC data)of laboratories participating in the routine chemistry and lipids and lipoproteins EQA activities of the national center for clinical laboratories from 2019 to 2021 was collected through clinet-EQA. For the analytes with biological variation(BV)data,compared the'percentage difference′ of EQA data and the'in-control coefficient of variation of the month′ of IQC data of each research analyte with the three levels evaluation criteria derived based on BV,and calculated the percentage difference passing rate and CV passing rate of all batches in each year. When the passing rate reaches 80%,the performance specifications of this level met the requirements of the recommended performance specifications of the analyte. For the analytes without BV data or analytes whose performance specifications at three levels derived based on BV could not be used as recommended standards,the recommended performance specifications are derived based on the current state of the art. After obtaining the recommended TEa and allowable CV for each analyte,used the formula | Bias|≤ TEa-z? CV to derive the recommended allowable bias. Results:The results of TEa ( CV)% recommended by 34 analytes are as follows:K4.7(2),Na4(1.5),Cl4(1.4),Ca5(2),P9.6(3.9),Glu6.4(2.5),Urea8(3),UA12(4.1),Cre11(3.3),TP5(2),Alb5.2(2.4),TC8.6(2.7),TG13.5(5),HDL-C16.5(4.3),LDL-C20.5(6.2),ApoAⅠ16(5.3),ApoB 17.1(5.5),Lp(a) 24.1(10.4),TBil 12.4(5),DBil 20(7.3),ALT16(5),AST13.5(4.8),ALP17.5(4.8),AMY13.1(3.3),CK11.3(3.8),LDH11(3.9),CHE13.4(5.3),LIP20(6.9),Fe13.3(5.2),Mg14(4.5),Cu17.9(6.8),Zn15.1(6.4),γ-GGT10(3.3),α-HBDH18(5.8).The formula | Bias|≤ TEa-z? CV is used to derive the allowable bias of 34 analytes. Conclusions:For 34 clinical routine chemistry quantitative analytes,the allowable total error,allowable imprecision and allowable bias that meet the current state of the art of Chinese laboratories are recommended.

Establishing allowable total error for serum total folate in external quality assessment / 中华检验医学杂志

Objective:To establish the allowable total error (TEa) of the national external quality assessment (EQA) program in line with the current quality level of serum folate measurement in China.Methods:The data of serum total folate test in the clinical laboratory of a hospital in Beijing in 2016 were collected, and the Stata SE 15 software was used for Monte Carlo simulation to obtain the false-negative rate under different bias and inaccuracy conditions. The Origin Pro 9.1 software was used to make the contour figure. The TEa of serum total folate test is derived based on the acceptable false-negative rate. National EQA data of serum total folate in 2020 were collected to calculate the pass rate of participating laboratories and the laboratory pass rate of quality control products at each level under the five TEa derived from the analysis performance on clinical outcomes, biological variation, and the evaluation criterion of national EQA.Results:Based on the influence of analytical performance on clinical outcomes, the TEa was 10%. Under this TEa, the pass rate of the first EQA program of serum total folate in 2020 was more than 80%, and the pass rate of the second time was 73.1%. Under the minimum (46.57%) and appropriate level of TEa (15.52%) derived from biological variation and national EQA evaluation criterion, the pass rate of serum total folate in the two EQA programs in 2020 exceeded 85%.Conclusion:The analytical performance of serum total folate in China cannot meet the requirements of TEa derived based on the effect of analytical performance on clinical outcomes. An appropriate level of TEa derived based on biological variation (15.52%) is suggested as the recommended criterion for the TEa of serum total folate test.

Clinical Application of Overlapping Confidence Intervals for Monitoring Changes in Serial Clinical Chemistry Test Results

BACKGROUND: Interpretation of changes in serial laboratory results is necessary for both clinicians and laboratories; however, setting decision limits is not easy. Although the reference change value (RCV) has been widely used for auto-verification, it has limitations in clinical settings. We introduce the concept of overlapping confidence intervals (CIs) to determine whether the changes are statistically significant in clinical chemistry laboratory test results.METHODS: In total, 1,202,096 paired results for 33 analytes routinely tested in our clinical chemistry laboratory were analyzed. The distributions of delta% absolute values and cut-off values for certain percentiles were calculated. The CIs for each analyte were set based on biological variation, and data were analyzed at various confidence levels. Additionally, we analyzed the data using RCVs and compared their clinical utility.RESULTS: Most analytes had low indexes of individuality with large inter-individual variability. The 97.5th percentile cut-offs for each analyte were much larger than conventional RCVs. The percentages of results exceeding RCV(95%) and RCV(99%) corresponded to those with no overlap at the 83.4% and 93.2% confidence levels, respectively.CONCLUSIONS: The use of overlapping CIs in serial clinical chemistry test results can overcome the limitations of existing RCVs and replace them, especially for analytes with large intra-individual variation.

Persistent median artery inside the carpal tunnel: description and surgical implications

The median artery is usually a transient vessel during the embryonic period. However, this artery can persist in adult life as the persistent median artery. This paper aims to describe this relevant anatomical variation for surgeons, review the literature and discuss its clinical implications. A routine dissection was performed in the upper left limb of a male adult cadaver of approximately 50-60 years of age, embalmed in formalin 10%. The persistent median artery was identified emerging as a terminal branch of the common interosseous artery with a path along the ulnar side of the median nerve. In the wrist, the persistent median artery passed through the carpal tunnel, deep in the transverse carpal ligament. The dissection in the palmar region revealed no anastomosis with the ulnar artery forming the superficial palmar arch. The common digital arteries emerged from the ulnar artery and the persistent median artery. Such variation has clinical and surgical relevance in approaching carpal tunnel syndrome and other clinical disorders in the wrist.

Elevated High-Sensitivity Troponin I in the Stabilized Phase after an Acute Coronary Syndrome Predicts All-Cause and Cardiovascular Mortality in a Highly Admixed Population: A 7-Year Cohort / A Troponina I de Alta Sensibilidade Elevada na Fase Estabilizada após Síndrome Coronariana Aguda Prevê Mortalidade por Todas as Causas e Mortalidade Cardiovascular em uma População Altamente Miscigenada: Uma Coorte de 7 Anos

Abstract Background: High-sensitivity cardiac troponin I (hs-cTnI) has played an important role in the risk stratification of patients during the in-hospital phase of acute coronary syndrome (ACS), but few studies have determined its role as a long-term prognostic marker in the outpatient setting. Objective: To investigate the association between levels of hs-cTnI measured in the subacute phase after an ACS event and long-term prognosis in a highly admixed population. Methods: We measured levels of hs-cTnI in 525 patients 25 to 90 days after admission for an ACS event; these patients were then divided into tertiles according to hs-cTnI levels and followed for up to 7 years. We compared all-cause and cardiovascular mortality using Cox proportional hazards models and adopting a significance level of 5%. Results: After a median follow-up of 51 months, patients in the highest tertile had a greater hazard ratio (HR) for all-cause mortality after adjustment for age, sex, known cardiovascular risk factors, medication use, and demographic factors (HR: 3.84, 95% CI: 1.92-8.12). These findings persisted after further adjustment for estimated glomerular filtration rate < 60 ml/min/1.73 m2 and left ventricular ejection fraction < 0.40 (HR: 6.53, 95% CI: 2.12-20.14). Cardiovascular mortality was significantly higher in the highest tertile after adjustment for age and sex (HR: 5.65, 95% CI: 1.94-16.47) and both in the first (HR: 4.90, 95% CI: 1.35-17.82) and second models of multivariate adjustment (HR: 5.89, 95% CI: 1.08-32.27). Conclusions: Elevated hs-cTnI levels measured in the stabilized phase after an ACS event are independent predictors of all-cause and cardiovascular mortality in a highly admixed population.

Resumo Fundamento: A troponina cardíaca de alta sensibilidade I (TnI-as) tem desempenhado um papel importante na estratificação de risco dos pacientes durante a fase intra-hospitalar da síndrome coronariana aguda (SCA), mas poucos estudos determinaram seu papel como marcador prognóstico de longo prazo no ambiente ambulatorial. Objetivo: Investigar a associação entre os níveis de TnI-as medidos na fase subaguda após um evento de SCA e o prognóstico a longo prazo, em uma população altamente miscigenada. Métodos: Medimos os níveis de TnI-as em 525 pacientes em um período de 25 a 90 dias após a entrada em hospital por um evento de SCA; esses pacientes foram então divididos em tercis conforme os níveis de TnI-as, e acompanhados por até 7 anos. Comparamos as mortalidades por todas as causas e cardiovascular através de modelos de riscos proporcionais de Cox e adotando um nível de significância de 5%. Resultados: Após um acompanhamento médio de 51 meses, os pacientes no tercil mais alto apresentaram uma taxa de risco (HR) maior para mortalidade por todas as causas, após ajustes para idade, sexo, fatores de risco cardiovascular conhecidos, uso de medicação e fatores demográficos (HR: 3,84 IC 95%: 1,92-8,12). Esses achados persistiram após um ajuste adicional para uma taxa de filtração glomerular (TFG) estimada < 60 ml/min/1,73 m2 e uma fração de ejeção do ventrículo esquerdo < 0,40 (HR: 6,53; IC95%: 2,12-20,14). A mortalidade cardiovascular foi significativamente maior no tercil mais alto, após ajustes para idade e sexo (RR: 5,65; IC95%: 1,94-16,47) e tanto no primeiro modelo de ajuste multivariado (HR: 4,90; IC 95%: 1,35-17,82) quanto no segundo (HR: 5,89; IC95%: 1,08-32,27). Conclusões: Níveis elevados de TnI-as, medidos na fase estabilizada após um evento de SCA, são preditores independentes de mortalidade por todas as causas e de mortalidade cardiovascular em uma população altamente miscigenada.

A Novel Method to Study the Effects of Cyclosporine on Gingival Overgrowth in Children / 대한소아치과학회지

Previous studies to elucidate the etiology of cyclosporine(Cs)-induced gingival overgrowth in children have not completely excluded all factors that may cause differences among individuals. This study examined the effect of cyclosporine on the metabolism of type 1 collagen(CoL-I) in experimental models that controlled the effects of biological variations on individuals. Five 5-week-old male Sprague-Dawley rats were administered Cs by gastric feeding for 6 weeks. Gingival specimens were harvested from the mandibular posterior area before beginning Cs administration and at 2, 4, and 6 weeks thereafter. Gingival fibroblasts were cultured from all the 20 biopsies collected from the gingiva. Half of the fibroblasts collected prior to the Cs administration were designated as Control. The other half of the fibroblasts were treated with Cs in vitro and called in vitro test group(Tt). The fibroblasts collected 2, 4, and 6 weeks after the Cs administration were called in vivo test groups : T2, T4, T6, respectively. Immunofluorescence microscopy was used to detect CoL-I in all the fibroblasts. CoL-I was analyzed at both the gene and protein expression levels by real-time polymerase chain reaction and western blotting. Changes in CoL-I before and after Cs treatment were evaluated from the gingiva of each rat. There was no significant difference in gene expression of CoL-I in the control and test groups. CoL-I protein expression levels of fibroblasts increased in in vitro Cs treatment for each individual, and also increased in in vivo Cs treatment. In this study, the experimental method that control biological variations that can occur due to differences among individuals was useful. Subsequent studies on other factors besides CoL-I and in-depth studies in humans are needed.

Cardiovascular Autonomic Neuropathy Predicts Higher HbA1c Variability in Subjects with Type 2 Diabetes Mellitus

BACKGROUND: This study aimed to investigate the association between the presence and severity of cardiovascular autonomic neuropathy (CAN) and development of long-term glucose fluctuation in subjects with type 2 diabetes mellitus. METHODS: In this retrospective cohort study, subjects with type 2 diabetes mellitus who received cardiovascular autonomic reflex tests (CARTs) at baseline and at least 4-year of follow-up with ≥6 measures of glycosylated hemoglobin (HbA1c) were included. The severity of CAN was categorized as normal, early, or severe CAN according to the CARTs score. HbA1c variability was measured as the standard deviation (SD), coefficient of variation, and adjusted SD of serial HbA1c measurements. RESULTS: A total of 681 subjects were analyzed (294 normal, 318 early, and 69 severe CAN). The HbA1c variability index values showed a positive relationship with the severity of CAN. Multivariable logistic regression analysis showed that CAN was significantly associated with the risk of developing higher HbA1c variability (SD) after adjusting for age, sex, body mass index, diabetes duration, mean HbA1c, heart rate, glomerular filtration rate, diabetic retinopathy, coronary artery disease, insulin use, and anti-hypertensive medication (early CAN: odds ratio [OR], 1.65; 95% confidence interval [CI], 1.12 to 2.43) (severe CAN: OR, 2.86; 95% CI, 1.47 to 5.56). This association was more prominent in subjects who had a longer duration of diabetes (>10 years) and lower mean HbA1c ( < 7%). CONCLUSION: CAN is an independent risk factor for future higher HbA1c variability in subjects with type 2 diabetes mellitus. Tailored therapy for stabilizing glucose fluctuation should be emphasized in subjects with CAN.

Postprandial Lipid Concentrations and Daytime Biological Variation of Lipids in a Healthy Chinese Population

BACKGROUND: Several latest guidelines and consensus statements from Europe and the United States specify that there is no need for fasting prior to routine lipid tests. However, the latest Chinese guidelines still recommend fasting tests owing to a lack of local evidence. This study aimed to investigate postprandial lipid concentrations and daytime biological variation of lipids in a healthy Chinese population. METHODS: Venous blood samples were collected from 41 ostensibly healthy Chinese volunteers at five time points during the day (06:30, 09:00, 12:00, 15:00, and 18:30). The same batch of reagents was used to determine lipid concentrations. A nested ANOVA was performed to calculate within-subject biological variation (CVI) and between-subject biological variation (CVG). RESULTS: Postprandial concentrations of triglyceride were higher than fasting concentrations, with the maximum change occurring at 12:00 (0.5 hours after lunch, 0.21±0.65 mmol/L difference). The daytime biological variation of triglycerides was relatively high (CVI=25%, CVG=35.9%). The postprandial concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein A1, and apolipoprotein B were mostly lower than the fasting concentrations, and their daytime biological variations were relatively low (CVI=2.4–4.4%, CVG=11.8–18.7%). CONCLUSIONS: As most daytime lipid concentrations changed only slightly, non-fasting samples could be used for routine lipid tests. However, in cases of abnormal postprandial triglyceride concentrations, dietary factors and fasting time should be considered when interpreting the results.

Application of the Requirement of Biological Variation Determination in the Quality Management of Blood Cell Analyzer / 现代检验医学杂志

Objective To study application of the quality management of Blood Cell Analyzer according to the requirement of biological variation determination.Methods Collected the indoor imprecision value(CV％) from 8 items detected by blood cell analyzer during from April to Nov.of 2016,and the bias (Bias％) of 8 items of two EQA (external quality assessment) from the ministry of health in 2016.Then according to the 3 levels of the minium,appropriate and optimal quality specifications derived from the biological variability the rates of imprecision and bias were culculated.The pass rate of the imprecision and bias was calculated.By using mean bias and mean imprecision and biological variation 3 levels of total error (TEa) crite rion,and to calculate the corresponding σ and QGI value,so as to evaluate the performance of whole blood cell analyzer.Then improved the quality.Results For the imprecision value of 8 items,except the MCHC average value,all others were all 100 ％ meeting the appropriate level of quality requirements.For the bias value (Bias ％) from 8 items,except MCH,all others were over 80 ％ meeting the appropriate level of quality requirements.While for the calculated σ value,based on the best level of quality requirements,except the σ value of WBC was 4.6,the σ value of all other items were all＜3.Based on the appropriate level of quality requirements,except the σvalue of MCHC was 1.9,the value of σ of all other items were all＞ 3,and based on the minimal requirements,the σ value of all 8 items were all ＞3.After analysis,this blood cell analyzer,except that MCHC should use the minimal quality standard requirements,all other examination items could used the proper quality standard requirements,and the calculated QGI were all ＜0.8.Conclusion Based on the biological variation determination requirement and calculated σ and QGI value,this method could be used to more accurate quality evaluation of blood cell ana lyzer.Which is a higher levelof quality management,will be more conducive to quality improvement and better serve the clinical.

Study on the quality management of biological variation allowed total error in detection of serum lipid / 国际检验医学杂志

Objective To study on the application of biological variation total allowable error in quality management of serum lipid detection .Methods The σ score ,quality goal index (QGI) ,priority improvement measures and performance evaluation of lipid accuracy criteria were evaluated ,including cholesterol (CHOL) ,triglyceride (TG) ,high density lipoprotein (HDL‐C) ,low density lipoprotein (LDL‐C) ,which included in the standard of accuracy of the Ministry of Health in 2015 .The reason for unsatisfactory re‐sults of cholesterol (CHOL) test were analyzed .Results Based on the three levels of quality specifications derived in biological var‐iation ,when the total allowable error was located at an appropriate level ,the σ score of TG ,HDL‐C ,LDL‐C reached 6 ,it was not re‐quired for improvement .While the score of CHOL performance analysis was poor ,accuracy was required to give priority to impro‐ving .When the total allowable error reached the best level ,only the σ score of TG achieved “good” in the four items ,improvement of precision was needed .When the total allowable error was located at the lowest level ,the σ score of TG ,HDL‐C ,LDL‐C was grea‐ter than 6 ,the score of performance analysis reached the “excellent” .The σ score of CHOL (2 .9) had been closen to 3σ ,accuracy was required to be corrected .Conclusion The biological variation derived total allowable error is easy to meet the requirements of the quality management in serum lipid determination by current technologies and methods .The theory of 6σ quality can reflect the performance of detection indexes ,and improve the quality of analysis effectively .

Reference change values and quality standards for thyroid function assay / 国际检验医学杂志

Objective To evaluate the reference change values (RCV),individual indexes of TSH,T4,T3,FT3,and FT4 and the limitations of population-based reference ranges.Furthermore,to determine the quality standards based on the biological varia-tion.Methods Acorrding to intra-and inter-individual biological variations,and analytical variations ,RCV and individual indexes of TSH,T4,T3,free T3,and free T4 were calculated,and analytical variations of quality standards based on biological variation were induced.Results RCV of TSH,T4,T3,FT3,and FT4 is 54.0%,16.8%,26.8%,42.8%,23.8%,respectively.Individ-uality index is 0.78,0.45,0.49,0.47,0.45,respectively,and satisfied analytical variation based on biological variation is less than 9.6%,2.5%,4.4%,2.9%,4.0%,respectively.Conclusion When monitoring thyroid functions,the RCV values should be considered.It is important to recognize population-based reference ranges limitations for use in individuals.Quality standards based on biological variation should be meeted when laboratory analysis of variance is determined.

The value of the way for determination of target uncertainty and periodical review of the uncertainty in quality improvement / 国际检验医学杂志

Objective To discuss the value in quality improvement and continuous improvement through the way for determina-tion of target uncertainty in chemical quantitative detection project and regular evaluation of measurement uncertainty in different phase.Methods Based on the biological variability of quality specification and CNAS-TRL-001:CNAS technical report,to compare the five kinds of determination of target uncertainty.Method 1:the fundamental way(calculate the different levels of target impre-cision and bias);Method 2:biological variation of different grades of total allowable error;Method 3:the relative expanded uncer-tainty evaluation value based on target imprecision and bias;Method 4:the target relative expanded uncertainty based on biological variation of different grades;Method 5:the target relative expanded uncertainty based on the quality index of analysis.We used un-certainty evaluate index(UEI)to review the changes of uncertainty in different phase.Results The 14 conventional chemistry tests in 2013 with metrological traceability and participate in the Ministry of health EQA were as the target.There was no significant difference among the 2,3,4 method,the ratio of which reached the ideal value of uncertaninty target were not significantly different. In method 5,9 projects achieved the target of uncertainty requirements,accounted for 64.3%.TP,ALT,BUN,UA,CK,these5 pro-jects′UEI were less than 0,accounted for 35.7%;other 9 projects′UEI were more than 2.0%.Conclusion Method 5:the target relative expanded uncertainty based on the quality index of analysis which is based on WS/T403-2012 can give consideration to the quality standard of repeatability precision and bias in the laboratory at the same time,and is easy to be accepted for laboratory;method 4:the target relative expanded uncertainty based on biological variation of different grades is in the same way with the eval-uation of test results uncertainty,is better than method 2 and 3;method 1 is the fundamental way,can give the specific reasons when the test results cannot get the target uncertainty.Use UEI to assess the changes of uncertainty in different phase is more sensitive to changes of the test results′accuracy and its usefulness needs to be confirmed in practice.

Recombinant E. coli expressing Vitreoscilla haemoglobin prefers aerobic metabolism under microaerobic conditions: A proteome-level study.

Vitreoscilla haemoglobin (VHb) expression in heterologous host was shown to enhance growth and oxygen utilization capabilities under oxygen-limited conditions. The exact mechanism by which VHb enhances the oxygen utilization under oxygen-limiting conditions is still unknown. In order to understand the role of VHb in promoting oxygen utilization, changes in the total protein profile of E. coli expressing the vgb gene under its native promoter was analysed. Two-dimensional difference gel electrophoresis (2D DIGE) was employed to quantify the differentially expressed proteins under oxygen-limiting conditions. Overexpression of proteins involved in aerobic metabolic pathways and suppression of proteins involved in non-oxidative metabolic pathways shown in this study indicates that the cells expressing VHb prefer aerobic metabolic pathways even under oxygen limitation. Under these conditions, the expression levels of proteins involved in central metabolic pathways, cellular adaptation and cell division were also found to be altered. These results imply that Vitreoscilla haemoglobin expression alters aerobic metabolism specifically, in addition to altering proteins involved in other pathways, the significance of which is not clear as of now.

Variabilidad biológica de aldolasa sérica: su utilidad en la interpretación de los resultados / Biological variation of serum aldolase: its use for interpretation of the results / Variabilidade biológica de aldolase sérica: sua utilidade na interpretagáo dos resultados

El objetivo de este trabajo fue determinar la variabilidad biológica (VB) de Aldolasa (ALD) en individuos sanos, el índice de individualidad (II) del analito y evaluar la utilidad del intervalo de referencia poblacional (IRP) considerando al IRP de los analitos útil cuando el II es > 1,4 y de poca utilidad si es <0,6. También se evaluó el valor de referencia para el cambio (VRC) en la interpretación de dos determinaciones seriadas del mismo individuo, especialmente en el seguimiento de enfermedades músculo-esqueléticas en las que los niveles de creatinquinasa (CK) permanecen dentro del intervalo de referencia, mientras que los de ALD están elevados. Se obtuvieron 8 muestras de sangre de 10 individuos aparentemente sanos en días diferentes según protocolo preestablecido. Se determinó la actividad de ALD por método enzimático UV y se calcularon los parámetros de VB, II y VRC. Se obtuvo una VB intraindividual: 31%; VB interindividual: 21%, II 1.47 y VRC 90%. De acuerdo a los coeficientes de VB y el II obtenidos, los IRP son útiles para la interpretación de los resultados de ALD. Un resultado seriado será estadísticamente diferente del dato previo cuando el mismo tenga una diferencia mayor al 90% en relación al valor previo. El VRC entre dos determinaciones seriadas debe ser calculado en cada laboratorio con su propia variabilidad analítica para una correcta interpretación de los resultados.

The aim of this study was to determine the Biological Variation (BV) of Aldolase (ALD) in healthy patients, the individuality index (II) of the analyte and to assess how useful the population reference interval (PRI) is for the interpretation of the results, considering PRI useful when the II is >1.40 and useless when it is <0.6. Reference change values (RCV) were also assessed in the interpretation of two serial measurements of the same individual, specially in the monitoring of patients in which the serum level of Creatine Kinase (CK) remain within the reference range while ALD values are increased. Eight bloodsam-ples were obtained from ten apparently healthy subjects in different days according to a predetermined protocol. ALD activity was measured by an enzymatic UV method and BV, II and RCV were calculated. Intraindividual BV was 31 %, interindividual BV 21 %, II 1.47 and RCV 90%. Based on the results obtained for BV and II, PRIs are useful for the interpretation of ADL results. A serial result will be statistically different from the previous one when the variability between both results is higher than 90%. RCV must be determined in each laboratory using their own analytical variability in order to obtain a correct interpretation of the results.

O objetivo deste trabalho foi determinar a variabilidade biológica (VB) de Aldolase (ALD) em individuos saudáveis, o índice de individualidade (II) do analito e avaliar a utilidade do intervalo de referencia populacional (IRP) considerando o IRP dos analitos útil quando o II é > 1,4 e de pouca utilidade se é <0,6. Também foi avaliado o valor de referencia da variagáo (VRV) na interpretagáo de duas determinagóes seriadas do mesmo individuo, especialmente no seguimento de doengas músculo-esqueléticas nas quais os níveis de creatinoquinase (CK) permanecem dentro do intervalo de referencia, enquanto que os de ALD estáo elevados. Foram obtidas 8 amostras de sangue de 10 individuos aparentemente saudáveis em dias diferentes conforme protocolo preestabelecido. Determinou-se a atividade de ALD por método enzimático UV e se calcularam os parámetros de VB, II e VRC. Foi obtida uma VB intra-individual: 31 %; VB interindividual: 21 %, II 1.47 e VRV 90%. De acordo com os coeficientes de VB e o II obtidos, os IRP sáo úteis para a interpretagáo dos resultados de ALD. Um resultado seriado será estatisticamente diferente do dado prévio quando o mesmo tenha uma diferenga maior a 90% em relagáo ao valor prévio. O VRV entre duas determinagóes seriadas deve ser calculado em cada laboratório com sua própria variabilidade analítica para uma correta interpretagáo dos resultados.

Analytical quality specifications in laboratory medicine / 中华检验医学杂志

specifications are essential for total quality management in laboratory medicine. A consensus among worldwide professionals has been achieved and a hierarchy of strategies for setting analytical quality specifications has been proposed based on their relevance to medical decision-making. Quality specifications derived from biological variations have been widely accepted because of their objectivity and practicability and have more and more been used in the quality management in laboratory medicine.