HCO3 (mg/dL) |
Formula:
Expected PCO2 = Baseline PCO2 + ((Measured bicarbonate - 24) x 0.6)
Default value for Baseline PCO2 is 40.
Interpretation: if the patient's PCO2 is lower than the expected result, the patient has a superimposed respiratory alkalosis. If it is higher, the patient has a superimposed respiratory acidosis.
Limit of compensation is 55. Thus, any result (expected PCO2) higher than 55 should be converted to 55.
Reference:
Oosthuizen, Nicholette M. "Approach to acid-base disorders?A clinical chemistry perspective." Continuing Medical Education 30(7) (2012): 230-234.