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Abstract: PO1181

Pseudo-Hypobicarbonatemia with Severe Hypertriglyceridemia Corrected by Insulin Infusion

Session Information

Category: Fluid, Electrolyte, and Acid-Base Disorders

  • 902 Fluid, Electrolyte, and Acid-Base Disorders: Clinical


  • Poznanski, Noah John, Marshall University Joan C Edwards School of Medicine, Huntington, West Virginia, United States
  • Eldib, Howide, Marshall University Joan C Edwards School of Medicine, Huntington, West Virginia, United States
  • Al sanani, Ahlim, Marshall University Joan C Edwards School of Medicine, Huntington, West Virginia, United States

Anion gap metabolic acidosis (AGMA) is a condition characterized by low serum bicarbonate and unaccounted anions in the blood. Lactate or ketones are the most common anions causing AGMA. Severe hypertriglyceridemia and paraproteinemia can result in Pseudo-hypobicarbonatemia due to interference by these components when the commonly used enzymatic assay is utilized for serum bicarbonate measurement. The calculated bicarbonate derived from blood gas machines show accurate bicarbonate level. It is very important to recognize Pseudo- hypobicarbonatermia to avoid expensive work-up.

Case Description

A 42-year-old-male patient with a past medical history significant for diabetes mellitus type 2, obesity, and hyperlipidemia. The patient presented with nausea, vomiting and epigastric pain. Physical examination was significant for tenderness in the epigastrium and xanthelasma.
The basic metabolic profile (BMP) was significant for Na+ 127meq/L, Cl- 94mEq/L, HCO3- 9mEq/L, glucose 408mg/dL, BUN 10mg/dL, creatinine 0.87mg/dL and AGAP 24. A lipid panel showed a cholesterol 461mg/dL and triglycerides 4061mg/dL. Lipase and amylase were 1183U/L and 202U/L respectively. Urinalysis revealed trace ketones. CT abdomen revealed peripancreatic stranding. The patient was diagnosed with AGMA due to diabetic ketoacidosis and pancreatitis secondary to hypertriglyceridemia. An arterial blood gas analysis (ABG) subsequently revealed a pH 7.39, paCO2 40, PaO2 73 and a HCO3- 24.
A significant dissociation between the calculated and measured bicarbonate was noted. Following aggressive lowering of the triglycerides, with Insulin infusion there was an immediate resolution of the pseudo-hypobicarbonatemia and anion gap metabolic acidosis.


This measurement error is due to the mechanism by which the analyzer interprets the bicarbonate level in the serum. Most analyzers utilize either anion-selective electrode (ISE) or function via an enzymatic/photometric method. High amounts of lipid particles may cause light scattering altering the photometric analysis. This likely caused the discrepancy between the enzymatic/photometric measured serum bicarbonate and the calculated bicarbonate of the aqueous phase ISE analyzer used by the ABG. Clinicians should be able to recognize that its essential to obtain a blood gas sample for determination of the acid-base status to avoid expensive work up.