Abstract：
The aim was to evaluate the stability of serum bicarbonate at room temperature, depending on time to centrifugation and air exposure.
Stability study was conducted in the laboratory of Clinical Hospital Centre Rijeka, Croatia in January-February 2022. Nine samples from 10 volunteers were collected in clot activator gel tubes (Greiner Bio-One). Bicarbonate was measured on Beckman Coulter AU480 (Beckman Coulter, Brea, USA). Three tubes were left at room temperature for 30 min, three tubes for 2 h, three tubes for 4 h until centrifugation. First tube from first group (baseline) was measured immediately after centrifugation. Other measurements were expressed as percentage deviation (PD%) from baseline. First tube was remeasured after 1 and 2 h (OT_0h_1h; OT_0h_2h). Second and third tubes were opened 1 and 2 h after centrifugation (C_0h_1h; C_0h_2h). Second group of tubes was processed the same way with 2-hour centrifugation delay (WB_2h; OT_2h_1h; OT_2h_2h; C_2h_1h; C_2h_2h), and third group with 4-hour delay (WB_4h; OT_4h_1h; OT_4h_2h; C_4h_1h; C_4h_2h). PD% was compared to Maximum Permissible Difference (MPD=5.69%). MedCalc statistical software was used (MedCalc, Ostend, Belgium).
Bicarbonate baseline mean value (range) was 27.3 (23.4-29.6) mmol/L. Obtained PD% (95%CI) were: C_0h_1h 0.46 (-1.21, 2.12); C_0h_2h 0.18 (-2.22, 2.57); OT_0h_1h -6.46 (-7.57, -5.36); OT_0h_2h -10.67 (-12.13, -9.21); WB_2h -0.15 (-2.04, 1.74); C_2h_1h 0.01 (-1.52, 1.54); C_2h_2h -0.40 (-2.65, 1.85); OT_2h_1h -5.43 (-7.30, -3.55); OT_2h_2h -11.32 (-13.57, -9.07); WB_4h -0.85 (-3.28, 1.58); C_4h_1h -2.52 (-4.93, 0.11); C_4h_2h -3.02 (-5.62, 0.43); OT_4h_1h -7.34 (-9.64, -5.05); OT_4h_2h -11.85 (-14.38, -9.33).
Serum bicarbonate is stable for 4 h in closed uncentrifuged tubes, another 2 h in closed tubes after centrifugation, and is unstable within 1 h in opened tube.
Stability study was conducted in the laboratory of Clinical Hospital Centre Rijeka, Croatia in January-February 2022. Nine samples from 10 volunteers were collected in clot activator gel tubes (Greiner Bio-One). Bicarbonate was measured on Beckman Coulter AU480 (Beckman Coulter, Brea, USA). Three tubes were left at room temperature for 30 min, three tubes for 2 h, three tubes for 4 h until centrifugation. First tube from first group (baseline) was measured immediately after centrifugation. Other measurements were expressed as percentage deviation (PD%) from baseline. First tube was remeasured after 1 and 2 h (OT_0h_1h; OT_0h_2h). Second and third tubes were opened 1 and 2 h after centrifugation (C_0h_1h; C_0h_2h). Second group of tubes was processed the same way with 2-hour centrifugation delay (WB_2h; OT_2h_1h; OT_2h_2h; C_2h_1h; C_2h_2h), and third group with 4-hour delay (WB_4h; OT_4h_1h; OT_4h_2h; C_4h_1h; C_4h_2h). PD% was compared to Maximum Permissible Difference (MPD=5.69%). MedCalc statistical software was used (MedCalc, Ostend, Belgium).
Bicarbonate baseline mean value (range) was 27.3 (23.4-29.6) mmol/L. Obtained PD% (95%CI) were: C_0h_1h 0.46 (-1.21, 2.12); C_0h_2h 0.18 (-2.22, 2.57); OT_0h_1h -6.46 (-7.57, -5.36); OT_0h_2h -10.67 (-12.13, -9.21); WB_2h -0.15 (-2.04, 1.74); C_2h_1h 0.01 (-1.52, 1.54); C_2h_2h -0.40 (-2.65, 1.85); OT_2h_1h -5.43 (-7.30, -3.55); OT_2h_2h -11.32 (-13.57, -9.07); WB_4h -0.85 (-3.28, 1.58); C_4h_1h -2.52 (-4.93, 0.11); C_4h_2h -3.02 (-5.62, 0.43); OT_4h_1h -7.34 (-9.64, -5.05); OT_4h_2h -11.85 (-14.38, -9.33).
Serum bicarbonate is stable for 4 h in closed uncentrifuged tubes, another 2 h in closed tubes after centrifugation, and is unstable within 1 h in opened tube.
摘要：
目的：目的是评估血清碳酸氢盐在室温下的稳定性，取决于时间离心和空气暴露。
方法：在Rijeka临床医院中心实验室进行稳定性研究，克罗地亚，2022年1月至2月。将来自10名志愿者的9个样品收集在凝块活化剂凝胶管(GreinerBio-One)中。在贝克曼库尔特AU480上测量碳酸氢盐(贝克曼库尔特，Brea,美国）。三管在室温下放置30分钟，三个管2小时，三管4小时，直到离心。在离心后立即测量来自第一组(基线)的第一管。其他测量值表示为与基线的百分比偏差(PD%)。在1和2小时后重新测量第一管(OT_0h_1h;OT_0h_2h)。离心(C_0h_1h;C_0h_2h)后1和2小时打开第二和第三管。第二组试管以相同的方式处理，离心延迟2小时(WB_2h;OT_2h_1h;OT_2h_2h;C_2h_1h;C_2h_2h)，第三组延迟4小时(WB_4h;OT_4h_1h;OT_4h_2h;C_4h_1h;C_4h_2h)。将PD%与最大允许差异(MPD=5.69%)进行比较。使用MedCalc统计软件(MedCalc，奥斯坦德,比利时)。
结果：碳酸氢盐基线平均值（范围）为27.3（23.4-29.6）mmol/L。获得的PD％（95CI）为：C_0h_1h0.46（-1.21，2.12）；C_0h_2h0.18（-2.22，2.57）；OT_0h_1h-6.46（-7.57，-5.36）；OT_0h_2h_2h-10.67（-12.13，-9.21）；WB_248-0.85_h-1.15（-
结论：血清碳酸氢盐在封闭的未离心试管中稳定4小时，离心后在封闭管中再放置2小时，在开管1h内不稳定。
方法：在Rijeka临床医院中心实验室进行稳定性研究，克罗地亚，2022年1月至2月。将来自10名志愿者的9个样品收集在凝块活化剂凝胶管(GreinerBio-One)中。在贝克曼库尔特AU480上测量碳酸氢盐(贝克曼库尔特，Brea,美国）。三管在室温下放置30分钟，三个管2小时，三管4小时，直到离心。在离心后立即测量来自第一组(基线)的第一管。其他测量值表示为与基线的百分比偏差(PD%)。在1和2小时后重新测量第一管(OT_0h_1h;OT_0h_2h)。离心(C_0h_1h;C_0h_2h)后1和2小时打开第二和第三管。第二组试管以相同的方式处理，离心延迟2小时(WB_2h;OT_2h_1h;OT_2h_2h;C_2h_1h;C_2h_2h)，第三组延迟4小时(WB_4h;OT_4h_1h;OT_4h_2h;C_4h_1h;C_4h_2h)。将PD%与最大允许差异(MPD=5.69%)进行比较。使用MedCalc统计软件(MedCalc，奥斯坦德,比利时)。
结果：碳酸氢盐基线平均值（范围）为27.3（23.4-29.6）mmol/L。获得的PD％（95CI）为：C_0h_1h0.46（-1.21，2.12）；C_0h_2h0.18（-2.22，2.57）；OT_0h_1h-6.46（-7.57，-5.36）；OT_0h_2h_2h-10.67（-12.13，-9.21）；WB_248-0.85_h-1.15（-
结论：血清碳酸氢盐在封闭的未离心试管中稳定4小时，离心后在封闭管中再放置2小时，在开管1h内不稳定。
