Bicarbonate Measurement
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þ Partially filled vacutainer tubes may cause falsely low HC03 levels.  Author
suggests correcting by adding 0.5-0.6 mmol/L to the HCO3 level and subtract
0.2-0.3 from the anion gap for every cc of air in the vacutainer.  This has
not been tested for acidotic patients.
[Herr, RD.  Pseudometabolic acidosis caused by underfill of vacutainer tubes.
Ann Emerg Med 1992; 21:177.]