Table 2.

Comparison of hemoglobin, potassium, and sodium concentration measurements provided by the BGA in three critical care units with different preanalytical processes

	Cardiac Surgery OR n = 53	10-bed ICU n = 178	37-bed ICU/Step 1 n = 260	37-bed ICU/Step 2 n = 278
Time for results (min)
POCT	2 [2; 2]	5 [4; 7]*	24 [13; 38]*	15 [5; 29]*
Central lab.	82 [58; 130]	80 [63; 108]	112 [90; 135]	119 [80; 144]
Hemoglobin conc. (g/L)
POCT	129 [120–137]	108 [99–121]	115 [96–138]	93 [81–116]
Central lab.	126 [116–134]	104 [95–116]	101 [82–112]	91 [79–110]
Bias [limits of agreement]	−3 [−6; 1]	−5 [−28; 17]	−19 [−64; 27]*	− 3 [−10; 5]
Potassium conc. (mmol/L)
POCT	4.1 [3.9–4.3]	na	4 [3.5–4.3]	4.2 [3.8–4.7]
Central lab.	4.2 [4–4.5]	na	4.1 [3.7–4.4]	4.3 [3.9–4.8]
Bias [limits of agreement]	0.1 [−0.1; 0.4]		0.1 [−0.1; 0.4]	0.1 [−0,3; 0,5]
Sodium conc. (mmol/L)
POCT	139 [137–140]	na	138 [135–142]	136 [134–139]
Central lab.	139 [137–140]	na	138 [135–142]	138 [135–140]
Bias [limits of agreement]	0 [−3; 3]		0 [−3; 3]	1 [−2; 4]

Results are expressed as the median [IQR] or bias [inferior limits of agreement; superior limits of agreement]. n refers to the number of paired analyses

OR operative room, ICU intensive care unit, POCT point-of-care testing, lab. laboratory, conc. concentration, med. median, na non-available

* p < 0.001 (Cardiac Surgery OR vs. 10- or 37-bed ICU)