Inter-instrumental comparison for the measurement of electrolytes in patients admitted to the intensive care unit

Figures & data

Figure 1 Bland-Altman plot of sodium (A) and potassium (B).

Abbreviations: AA, auto-analyzer; ABG, arterial blood gas; SD, standard deviation.

Figure 2 Mountain plot for sodium (A) and potassium (B).

Abbreviations: AA, auto-analyzer; ABG, arterial blood gas.

Figure 3 Passing and Bablok regression analysis of sodium (A) and potassium (B).

Abbreviations: AA, auto-analyzer; ABG, arterial blood gas.

Table 1 Comparision of statistics obtained from AA and ABG analyzer for sodium and potassium

Electrolyte/machine	Valid	Mean	Standard error of mean	Median	Mode	Standard deviation	Variance	Range	Minimum	Maximum
Sodium
AA	98	144.459	0.7708	145.000	143.0	7.6309	58.230	41.0	124.0	165.0
ABG analyzer	98	140.134	0.7658	139.750	135.5	7.5812	57.475	38.2	118.1	156.3
Potassium
AA	98	3.632	0.0533	3.550	3.4a	0.5277	0.278	2.6	2.7	5.3
ABG analyzer	98	3.588	0.0675	3.435	3.4a	0.6684	0.447	4.5	2.0	6.5

Notes:

a Multiple modes exist. The smallest value is shown.

Abbreviations: AA, auto-analyzer; ABG, arterial blood gas.