Performance evaluation of serum progesterone measurement by ID-LC/MS/MS candidate reference methods and their clinical application value / 中华检验医学杂志

Objective:To establish a candidate reference method for serum progesterone using isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) in our laboratory, validate the analytic performance of five clinical routine detection systems to explore the comparability of serum progesterone detection by different detection systems.Methods:A candidate reference method for serum progesterone using ID-LC/MS/MS method was established. The sample was pretreated by liquid-liquid extraction method, and the reversed phase liquid phase separation in positive ion mass spectrometry mode was used to detect progesterone in human serum, and the detection time of a single sample was controlled within 5 minutes by gradient elution. In order to improve the accuracy of the method, the bracketing calibration method (BCM) was used to establish the standard curve. The sensitivity, accuracy, precision and specificity of BCM and classical calibration curve method were evaluated according to CLSI C62-A, EP15-A2, EP6-A2 and EP9-A3, and the analytical performance and comparability of five clinical routine progesterone detection systems were evaluated,compared with ID-LC/MS/MS method, the bias at medical decision level 2 and 25 ng/ml was evaluated to see if they were <1/2TEa (12.5%).Results:The limit of detection (LOD) of ID-LC/MS/MS was 0.005 ng/ml. The recoveries of BCM method and classical calibration curve method are 97.95%-101.58% and 96.88%-110.70%, respectively. The measurement results of BCM method for certified reference materials are within its declared uncertainty range. The intra-and inter-assay coefficient of variation ( CV) of BCM method was less than 3.0%, which was better than that of classical calibration curve method ( CV: 2.48%-9.33%). The precision and linear range of the five clinical routine detection systems can meet the detection requirements. The measurement bias of detection system 1, 3 and 5 at 25 ng/ml of medical decision level was less than 1/2TEa, and the measurement bias at 2 ng/ml of medical decision level was more than 1/2TEa. The measurement bias of detection system 2 and 4 at two medical decision levels was less than 1/2TEa. Conclusion:The candidate reference method for serum progesterone ID-LC/MS/MS established in our laboratory meets the requirements of the reference method. BCM has better detection performance than classical calibration curve method. The precision and linearity of the five progesterone clinical detection systems are satisfactory. The five clinical detection systems could meet the clinical requirements at the medical determination level of 25 ng/ml, however, only two of the five clinical detection systems meet the clinical requirements at the medical determination level of 2 ng/ml.

Moving Rate of Positive Patient Results as a Quality Control Tool for High-Sensitivity Cardiac Troponin T Assays

Background@#A small shift in high-sensitivity cardiac troponin T (hs-cTnT) assays can lead to different result interpretation and consequent patient management. We explored whether a small bias could be detected using conventional internal quality control (QC) procedures, evaluated the performance of moving average (MA)-based QC procedures, and proposed a new QC procedure based on the moving rate (MR) of positive patient results of hs-cTnT assays. @*Methods@#The ability of conventional QC to detect a 5 ng/L bias was examined using the 1 3s/ 22s/R4s multi-rule procedure as deviation rules.We developed MA and MR procedures for the hs-cTnT assay using eight months of patient data. The performance of different MA or MR procedures was investigated by calculating the median number of patient samples affected until a bias introduced into the dataset was detected (MNPed). After comparing the MNPed across different procedures, we selected an optimal MA or MR procedure for validation. Validation graphs were plotted using the minimum, median, and maximum number of results affected until bias detection. @*Results@#Our conventional QC procedures could not detect a positive bias of 5 ng/L. When a positive bias was introduced, MNPed was much higher using MA than using MR, with cut-off values of 5 ng/L and 14 ng/L, respectively. MR validation charts for optimal procedures provided insight into the MR performance. @*Conclusions@#The MR procedure could detect different errors with few false alarms. In the hs-cTnT assay, the MR procedure with a smaller cut-off value outperformed MA and conventional QC procedures for small bias detection.

Comparison plasma osmolality between freezing point depression method and different calculation formulas / 国际检验医学杂志

Objective Sixteen common blood osmotic pressure calculation formulas were investigated to evaluate the calculation formula of the plasma osmotic pressure formula and the freezing point depression method.The collected data were used to simulate a formula that was consistent with the patient′s plasma osmotic pressure.Methods The osmotic pressure of plasma was measured by the freezing point descent method.Plasma sodium (Na), potassium (K), chloride (Cl), glucose (Glu), and urea (Urea) concentrations were measured by using a Vitros 5.1dry chemistry analyzer.Sixteen formulas were used to calculate the corresponding plasma osmotic pressure.The Passing-Bablok regression was used to determine the goodness of fit and paired t test was performed with the measured values.A multiple linear regression and paired t test method was used to fit a formula that most closely matched the measured values.Results The formula of plasma osmotic pressure and the measured value was the most consistent with the formula 1.86 (CNa+CK) +CGlu+CUrea+10;the regression formula using multiple linear regression was 1.86CNa+2.75CK+1.16CGlu+0.92CUrea+5.77.Conclusion It is tentatively concluded that the formula 1.86CNa+2.75CK+1.16CGlu+0.92CUrea+5.77can be used as the formula for calculating plasma osmolality.

Clinical Evaluation of High-Sensitive Troponin T in Acute Myocardial Infarction / 实用医学杂志

Objective To investigate the diagnostic value of High-Sensitive Troponin T(hs-TnT)in acute myocardial infarction(AMI). Methods One hundred and sixty nine patients with serum hs-TnT concentration≥0.014 μg/L in early hospitalization were enrolled in this study.The ROC curve was used to compare the concentra-tion of hs-TnT with four heart enzyme(CK,CK-MB,LDH,AST)on the diagnostic efficacy to AMI. The differ-ence of hs-TnT in different clinical data groups were investigated using Mann-Whitney U rank test.Then the correla-tion between hs-TnT and Gensini score of Coronary angiography was investigated using the Spearman rank correla-tion test.Results The concentration of hs-TnT in patients with chest pain was significantly higher than that in non-AMI group(P<0.05).The AUC of each ROC curve was hs-TnT(0.806)>CK-MB(0.792)>CK(0.780)>AST (0.704)> LDH(0.684). The optimal diagnostic point of hs-TnT was 0.152 ug/L(sensitivity 0.659,specificity 0.894,Yuden index 0.553).There was a positive correlation between hs-TnT and Gensini scores in men,age>65 years old and the chest tightness group(P < 0.05). Conclusion The hs-TnT is better than four heart enzyme in early diagnosis of AMI and benefit early treatment of AMI.

Correlation and significance of combined detection of D-Dimer,cTnI and NT-ProBNP in acute coronary syndrome / 国际检验医学杂志

Objective To explore the significance of combined detection of D-Dimer,cardic troponin I(cTnI)and N-terminal pro-brain natriuretic peptide(NT-ProBNP)in acute coronary syndrome and the correlation between them.Methods 143 patients with acute coronary syndrome were selected as the observation group,and 40 CAG negative people as the control group.The difference between the two groups was compared and the correlation was analyzed.According to different diagnostics,patients in the observa-tion group were separated into 3 groups,unstable angina pectoris,non ST segment elevation myocardial infarction and ST segment elevation myocardial infarction.The correlation of D-Dimer,cTnI and NT-ProBNP with the severity of coronary artery disease was analyzed.Results The levels of D-Dimer,cTnI and NT-ProBNP in the observation group were higher than those in the control group,and the difference was statistically significant(P < 0.05 ).The severity of coronary artery disease had positive correlation with the test results (P <0.05).Conclusion The combined detection of D-Dimer,cTnI and NT-ProBNP could help to diagnose the acute coronary syndrome and the test result has a positive correlation with the severity of acute coronary syndrome.

The level of souble interleukin 7receptor in serum from lupus nephritis patients and clinical implication / 实用医学杂志

Objective To investigate the level of soluble interleukin 7 receptor (sIL-7R) in serum of lupus nephritis(LN)patients and evaluate its clinical significance. Methods sIL-7R level in serum of LN patients and healthy controls were measured by ELISA , while total 24 hours urinary protein and complement C3 of LN patients were measured by BN ProSpec. The level of sIL-7R correlation with SLEDAI, total 24 hours urinary protein and complement C3 were analyzed respectively. Results The levelof sIL-7R was higher in serum of LN patients than healthy controls (P < 0.01). Moreover, its expression in serum was increased in LN patients in active stage than in LN patients in stable stage (P < 0.05). The level of sIL-7R was positively assosicated with SLEDAI, total 24 hours urinary protein(P < 0.01, P < 0.05) and negatively with complement C3 (P < 0.05). Conclusion The level of sIL-7R is upregulated in serum in LN patients and correlated with disease activity and progression, so it may be expected to become a potential marker of disease in prediction.

Evaluation of quantitative detection limit and functional sensitivity of prealbumin and their clinical applications analysis / 国际检验医学杂志

Objective To evaluate the limit of blank (LoB),limit of detection (LoD),limit of quantitation(LoQ)and functional sensitivity (FS)of prealbumin (PA)detected by the Roche Modular P automatic biochemical analyzer.Methods According to the EP17A file of the American Clinical and Laboratory Standards Institute (CLSI),saline as the blank sample and a series of low con-centration samples were detected by the Roche Modular P automatic biochemical analyzer for determining LoB,LoD and LoQ.And FS was determined based on the domestic universal method .Results LoB of PA was 16.35 mg/L,LoD was 18.23 mg/L,LoQ was temporarily unable to evaluate and FS was 25.00 mg/L.The report scope and the report mode in clinic were affirmed by combi-ning with the low value of the reportable scope.Conclusion LoD of PA detected by the Roche Modular P automatic biochemical an-alyzer is established,which provides more valuable information for clinical diagnosis and treatment.Conducting the comparison of different evaluation methods determines the advantages and limitation of the practical application of different methods.

Establishment of blood β-hydroxybutyrate threshold for diagnosis of type 2 diabetes ketoacidosis / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish of blood beta hydroxybutyrate (βOHB) threshold for diagnosing type 2 diabetes ketoacidosis (DKA) and explore the relationship between βOHB levels and the severity of DKA.</p><p><b>METHODS</b>Correlation analysis was performed between serum βOHB and [HCO(3)] in type 2 diabetic patients admitted in the emergency department in the past year. Regression equation was used to calculate the concentration of βOHB corresponding to a [HCO(3)] level of 18.0, 15, and 10.0 mmol/L, and βOHB concentration corresponding to a [HCO(3)] level of 18.0 mmol/l was used as the DKA diagnostic threshold.</p><p><b>RESULTS</b>The serum βOHB level and [HCO3] concentration showed a good correlation (R²=0.7023, P<0.001). βOHB concentrations that corresponded to a [HCO(3)] level of 18.0, 15, and 10.0 mmol/L were 3.0, 4.70, and 7.5 mmol/L, respectively, in accordance with the severity of DKA. Combined with the blood glucose concentration ≥ 13.9 mmol/L, a blood βOHB≥3.0 mmol/L showed a sensitivity of 99%, specificity of 86%, and total effectiveness of 92.81% for diagnosing DKA.</p><p><b>CONCLUSION</b>A serum βOHB level above 3.0 mmol/L can be used as the diagnostic threshold of DKA. βOHB can serve as an index for assessing the severity of DKA.</p>