The answer may be no, as long as you have a serum HCO3. In this retrospective study, linear regression was used to to assess serum HCO3 as a predictor of venous pH. Logistic regression was also used to evaluate serum HCO3 as a predictor of DKA. Using a HCO3 cutoff of <18 mmol/L had a sensitivity of 91.8% and specificity of 91.7% for detecting a pH <7.3. A HCO3 < 8 had a sensitivity of 95.2 % and specificity of 96.7 % for detecting a pH <7.1.
References
Von Oettingen J, Wolfsdorf J, Feldman, H and E Rhodes. Use of Serum Bicarbonate to Substitute for Venous pH in New-Onset Diabetes. Pediatrics 2015; 136: e371-e378.
