blood gas vs. serum electrolytes

26 Mar

–not a lot of data
–pubmed biopsy produced only 2 articles

–“Diagnostic accuracy of venous blood gas electrolytes for identifying diabetic ketoacidosis in the emergency department”
–looked at 46 DKA patients, compared serum and VBG electrolytes

  • sensitivity of VBG electrolytes for diagnosing DKA: 97.8%
  • specificity of VBG electrolytes for diagnosing DKA: 100%
  • Correlation coefficients between VBG and serum chemistry
    • sodium 0.90
    • chloride 0.73
    • bicarbonate 0.94
    • anion gap 0.81

–“Comparison of the point-of-care blood gas analyzer versus the laboratory auto-analyzer for the measurement of electrolytes”
–looked at 200 ICU patients, compared ABG and serum lab Na+ and K+

  • mean ABG sodium value was 131.28 (SD 7.33)
  • mean lab sodium value was 136.45 (SD 6.50) (p < 0.001).
  • mean ABG potassium value was 3.74 (SD 1.92)
  • mean lab potassium value was 3.896 (SD 1.848) (p = 0.2679).

–conclusions: no significant difference between the potassium values; however, the difference between the measured sodium was found to be significant
–decisions can be made by trusting the K+ values obtained from ABG (less so with the sodium)

–how close are blood gas electrolytes to the lab serum electrolytes?
not much data, seems close enough for acidosis, potassium
–not as good for sodium

Submitted by S. Lee.

Reference(s): article 1, article 2, picture


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