Spurious Low Serum Bicarbonate Level Due to Severe Hypertriglyceridemia: A Clinical Challenge

A Case of Profound Hypertriglyceridemia Causing Pseudohypobicarbonatemia

The light-scattering effect of hypertriglyceridemia may interfere with the photometric analysis of the electrolytes, leading to errors in laboratory values. We present a case of erroneously low bicarbonate levels due to the presence of severe hypertriglyceridemia. A 49-year-old male was admitted for knee cellulitis. A comprehensive metabolic panel showed very low bicarbonate of <5 mmol/L, and an elevated anion gap of 26 mmol/L. The lactic acid, salicylic acid, ethanol, and methanol levels were normal. The lipid panel showed a remarkably high triglyceride level of 4846 mg/dL. An arterial blood gas (ABG) showed a normal pH of 7.39 and a bicarbonate level of 28 mmol/L, which was inconsistent with the metabolic acidosis seen in the blood test. The discrepancy between acidosis seen in the metabolic panel and ABG was explained by a lab error in the measured bicarbonate levels, which occurs in the presence of elevated triglyceride levels. Most laboratories use either an enzymatic/ photometric or an indirect ion-selective electrode method to measure bicarbonate. Hyperlipidemia interferes with photometric analysis due to its light-scattering effect. An ABG analyzer uses a direct ion-selective electrode method that is free of the errors of a photometric analyzer. Knowing about conditions like hypertriglyceridemia, which can interfere with the measurement of electrolytes, is important in everyday clinical medicine, as it can prevent unnecessary investigation and intervention.

Mind the gap: A case of unexplained elevated anion gap without concomitant metabolic acidosis

Hypertriglyceridemia causing unexplained hypobicarbotinemia and elevated anion gap is rare. We report the case of a 33-year-old woman who presented with an unexplained high anion gap after a subacute gastrointestinal illness. An arterial blood gas showed a normal bicarbonate level, and a lipid panel resulted in a triglyceride level too high to read, establishing the diagnosis. Treatment included using triglyceride-lowering agents with normalization in the patient's serum bicarbonate levels.