Standardization of measurement procedures for serum uric acid: 8-year experience from Category 1 EQA program results in China

Performance of HDL-C measurements assessed by a 4-year trueness-based EQA/PT program in China

OBJECTIVES

A trueness-based EQA/PT program for high density lipoprotein cholesterol (HDL-C) was initiated. We analyzed the 4 year EQA/PT program to overview the measurement standardization for HDL-C in China.

METHODS

Two levels of freshly frozen, commutable serum external quality assessment/proficiency testing (EQA/PT) materials were prepared and determined by reference measurement procedure each year. The samples were delivered to clinical laboratories and measured 15 times in 3 days. The precision [coefficient of variation (CV)], trueness (bias), and accuracy [total error (TE)] were calculated and used to evaluate measurement performance. The pass rates of individual laboratories and peer groups were analyzed using the acceptable performance from the National Cholesterol Education Program (NCEP) and biological variation as the evaluation criteria.

RESULTS

More than 60% of laboratories use heterogeneous systems, and there was a decrease in the percentage from 2016 to 2019. About 95, 78, and 33% of laboratories met the minimum, desirable and optimum TE criteria derived from biological variation. The pass rates were 87.0% (84.7-88.8%), 58.7% (55.3-62.4%), and 97.3% (95.6-98.3%) that met the acceptable performance of TE, bias, and CV of NCEP. The homogeneous systems had higher pass rates of TE, bias, and CV than the heterogeneous groups in 2016, but they did not show apparent advantages in 2017-2019.

CONCLUSIONS

The trueness-based EQA/PT program can be used to evaluate the accuracy, reproducibility, and trueness of results. For some IVD manufacturers and individual laboratories, accuracy, especially trueness, are still problems. Efforts should be made to improve the situation and achieve better HDL-C measurement standardization.

Nutritional assessments in pregnancy and the risk of postpartum depression in Chinese women: A case-control study

Prevalence of postpartum depression (PD) in Chinese women is rising and its associated factors are not well known. In this study we aim to explore the associations between nutritional factors in pregnancy and the risk of PD in Chinese women.A case-control study was performed in our hospital during January 2016 to June 2019. A food frequency questionnaire was designed to collect food consumption before the childbirth preceding month. Nutrition related biochemical indicators including fasting blood-glucose (GLU), total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL), high density lipoprotein (HDL), and uric acid in the third trimester of pregnancy were detected. Logistic regression model was applied to compute odds ratio (OR) and its corresponding 95% confidence interval (CI).There were 565 participants in this study, which comprised 182 individuals with PD and 383 individuals without. Patients with PD had higher odds of increased GLU (OR=2.62, 95%CI = 1.67-4.11), TC (OR = 1.73 95%CI = 1.22-2.46), TG (OR = 2.43, 95%CI = 1.55-3.81), and LDL (OR = 3.41, 95%CI = 2.09-5.57), but decreased HDL (OR = 3.41, 95%CI = 2.09-5.57) during pregnancy. With respect to uric acid, there was lack of no statistical association (OR = 2.23, 95%CI = 0.82-6.26). Food frequency questionnaire indicated a higher meat intake, but a lower vegetable, fruit, fish, and poultry intake in patients with PD during pregnancy.Increased GLU, TC, TG, and LDL, but decreased HDL in later stages of pregnancy might be associated with PD.

The Estimation of Postmortem Serum Urea via the Ultrafiltration of Hemolyzed Blood

Postmortem serum urea has been demonstrated as an objective indicator for the forensic diagnosis of cause of death. However, samples used in postmortem biochemical analysis are always affected by hemolysis. To investigate whether hemolysis affects the biochemical analysis of urea and to explore the feasibility of using ultrafiltration to process hemolyzed blood samples, three different levels of hemolyzed blood samples were used to assess the influence of hemolysis on postmortem biochemical analysis of urea, and two ultrafiltration methods were used to process the hemolyzed blood samples. Bias% was used to assess the interference of hemolysis. Our results showed that heavy hemolysis had a significant influence on the biochemical analysis of urea. Both ultrafiltration methods in the present study could significantly reduce the interference of hemolysis, with the |bias%| of methods A and B decreasing from 69.74% ± 99.14% to 12.18% ± 7.23% and 10.77% ± 8.09%, respectively, compared to the original serum. After regression correction, there was no significant difference between the urea concentration in the ultrafiltrates of the two ultrafiltration methods and that in the original serum, which suggested that the postmortem serum urea concentration could be estimated by the corrected urea concentration in the ultrafiltrate. The current study also provided possible pretreatment methods for postmortem biochemical analysis of other biomarkers in hemolyzed blood samples of forensic practice.

Analytical comparison between two hematological analyzer systems: Mindray BC-5180 vs Sysmex XN-1000

BACKGROUND

To compare the Mindray BC-5180 and Sysmex XN-1000 instruments by analyzing the results of complete blood count in the external quality assessment in Shandong Province in 2018.

METHODS

In the external quality assessment, 10 batches of quality control materials were issued throughout the year. The test items were WBC, RBC, Hb, PLT, and HCT. The laboratories using Mindray BC-5180 and Sysmex XN-1000 were screened, and the results were analyzed by t test, Passing-Bablok regression analysis, and Bland-Altman analysis.

RESULTS

Thirty-six laboratories using Mindray BC-5180 instruments and thirty-six laboratories using Sysmex XN-1000 instruments were screened, and the average difference between the two instruments results is not significant (P > 0.05, t test). Passing-Bablok regression analysis showed that the 95% confidence interval of the regression equation interception of each test item included 0, and the 95% confidence interval of the slope contained 1, r > 0.98, which showed that the correlation is good. The Bland-Altman analysis showed that both instruments had more than 95% of the points within the 95% consistency limit (WBC97.2%, RBC95.6%, PLT97.2%, Hb96.7%, HCT97.5%). Within the consistency limit, the absolute value of the difference between the Mindray BC-5180 instrument and the Sysmex XN-1000 instrument is WBC 0.14%, RBC 0.26%, PLT 2.7%, and Hb 1.9%. HCT is 0.69%, and the difference is clinically acceptable.

CONCLUSION

It can be considered that the two instruments have good correlation and consistency, and the two instruments can replace each other.