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Table 2 Comparison of hemoglobin, potassium, and sodium concentration measurements provided by the BGA in three critical care units with different preanalytical processes

From: Preanalytical conditions of point-of-care testing in the intensive care unit are decisive for analysis reliability

 

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]

  1. 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
  2. OR operative room, ICU intensive care unit, POCT point-of-care testing, lab. laboratory, conc. concentration, med. median, na non-available
  3. p < 0.001 (Cardiac Surgery OR vs. 10- or 37-bed ICU)