Objective To evaluate the interference of ALP on cTnI assays. Methods One normal mixed plasma sample and 2 abnormal mixed plasma samples with different cTnI levels were prepared, and then divided them into 8 groups respectively. One group was randomly chosen as control while different amounts of ALP were added into the other seven groups. The concentrations of cTnI and ALP in each plasma portion were detected by ACCESS2 (Beckman-Coulter, Inc ) and AXSYM (Abbott Laboratories )separately. The results of the seven tested groups were then compared with those of the control, so as to evaluate whether ALP could interfere with the cTnI assay. Results When the chemiluminescent Access cTnI assay was carried out for detection of normal plasma, the concentration of ALP was up to 3 716 U/L and did not interfere with the test results of cTnI [(0. 04 ±0.01) μg/L] compared with those of the control portion [(0. 04 ± 0. 01 ) μg/L] (t = 0. 40, P ＞ 0. 05 ). Once the concentration of ALP went beyond 917 U/L, the AXSYM cTnI assay results [( 0.08 ± 0. 01 ) μg/L] were higher than those of the normal control ( t =-4. 89, P＜0. 01 ); When the concentration of ALP was up to 3 534 U/L, the test results of abnormal plasma cTnI detected by the Access assay [( 13.41 ±0. 17) μg/L] did not show significant differences from those of the control [(13.48±0.16) μg/L] (t=0. 52,P＞0.05).Conclusions High concentration ofALP did not interfere with the Access cTnI assay or lead to false positive results. However, the high level of ALP( ＞ 917 U/L) could interfere with the AXSYM cTnI assay and cause a false positive result.

Objective:To explore the relationship between metabolic acidosis and cardiac valve calcification in maintenance hemodialysis (MHD) patients in the Pearl River Delta Region.Methods:Patients on MHD greater than 3 months who were treated in 10 blood purification centers in the Pearl River Delta Region from July 1 to September 30, 2019 were selected for this multicenter cross-sectional study. Based on a Doppler ultrasound, MHD patients were further divided into non-valve calcification group and valve calcification group. The demographics data, frequency of dialysis, blood pressure, single pool Kt/V(spKt/V), dialysis medications and laboratory data were collected and compared. Spearman correlation analysis was used to analyze the correlation between serum carbon dioxide combining power (CO 2CP) and cardiac valve calcification. Multivariate logistic regression model was used to analyze the influencing factors of cardiac valve calcification. Results:A total of 664 MHD patients were included in this study, with age of (57.0±14.2) years old and dialysis age of 43.0 (22.3, 71.7) months, including 395 males (59.5%) and 269 females (40.5%). Among them, there were 119 patients (17.9%) with diabetes and 186 patients (28.0%) with dialysis 2 times per week. There were 329 patients (49.5%) in the valve calcification group, and 335 patients (50.5%) in the non-valve calcification group. Compared to those in non-valve calcification group, valve calcification group had longer duration of dialysis, higher proportion of patients with dialysis 2 times per week, higher levels of diastolic blood pressure, fasting blood glucose, intact parathyroid hormone and ferritin, higher proportion of patients with blood CO 2CP<19 mmol/L (median CO 2CP), higher proportion of patients on usage of calcium channel blocker, angiotensin converting enzyme inhibitor/angiotensin receptor blocker, α-receptor blocker, β-receptor blocker, calcitriol and lanthanum carbonate (all P<0.05), while the levels of spKt/V, hemoglobin, serum CO 2CP, corrected calcium, blood phosphorus, blood alkaline phosphatase, albumin, total cholesterol, triacylglycerol, low-density lipoprotein, high-density lipoprotein, transferrin saturation, and the proportion of patients on usage of sevelamer and cinacalcet were lower (all P<0.05). Spearman analysis showed significant negative correlation between serum CO 2CP and valve calcification ( rs=-0.697, P<0.001). Multivariate logistic regression analysis showed that dialysis performed twice a week ( OR=2.789, 95% CI 1.232-6.305, P=0.014), blood total cholesterol ( OR=1.449, 95% CI 1.014-2.071, P=0.042), CO 2CP<19 mmol/L ( OR=22.412, 95% CI 10.640-47.210, P<0.001) were the influencing factor of valve calcification in MHD patients. Conclusions:MHD patients with cardiac valve calcification have significant acid loading. Metabolic acidosis is an independent influencing factor for cardiac valve calcification in MHD patients.