Potential Inaccuracies in Chloride Measurements in Patients with Severe Metabolic Acidosis
Table 1
Mean values and mean differences in electrolyte concentrations measured simultaneously by two analyzers for samples from acidic patients (pH < 7.40) or alkalemic patients (pH > 7.40).
pH < 7.40
pH > 7.40
Na+ (mmol/L)
Blood gas analyzer
135.7 ± 4.0
131.5 ± 6.5
Central laboratory analyzer
137.0 ± 3.6
133.0 ± 6.7
Mean difference
−1.27 ± 1.79
−1.46 ± 1.59
0.74
K+ (mmol/L)
Blood gas analyzer
3.6 ± 0.5
4.0 ± 0.5
Central laboratory analyzer
3.9 ± 0.6
4.3 ± 0.5
Mean difference
−0.25 ± 0.17
−0.27 ± 0.20
0.68
Cl− (mmol/L)
Blood gas analyzer
105.5 ± 3.6
101.2 ± 6.0
Central laboratory analyzer
102.5 ± 3.4
101.0 ± 6.0
Mean difference
3.10 ± 4.23
0.62 ± 1.55
0.004
Values are means ± SD. Na+: sodium; K+: potassium; Cl−: chloride.
