A rare case of persistent pseudohypobicarbonatemia arising from chemistry analyzer-specific interference.

Autor: Ma L; Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA; New York-Presbyterian Hospital, Weill Cornell Medicine, New York, NY, USA., Zhao Z; Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA; New York-Presbyterian Hospital, Weill Cornell Medicine, New York, NY, USA., Racine-Brzostek SE; Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA; New York-Presbyterian Hospital, Weill Cornell Medicine, New York, NY, USA., Yang HS; Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA; New York-Presbyterian Hospital, Weill Cornell Medicine, New York, NY, USA. Electronic address: hey9012@med.cornell.edu.
Jazyk: angličtina
Zdroj: Clinica chimica acta; international journal of clinical chemistry [Clin Chim Acta] 2021 Aug; Vol. 519, pp. 308-310. Date of Electronic Publication: 2021 May 26.
DOI: 10.1016/j.cca.2021.05.025
Abstrakt: Background: Major discrepancies between concentrations of serum total carbon dioxide (tCO 2 ) obtained from chemistry analyzers and calculated bicarbonate from blood gas analyzers should prompt laboratory investigation. Here, we present a rare case of pseudohypobicarbonatemia unrelated to the common causes such as hypertriglyceridemia and hyperproteinemia, but was caused by a low concentration of paraproteins.
Case: A 75-year-old man with persistent fevers was found to have a low concentration of serum tCO 2 (<10 mmol/l) with a normal pH and calculated bicarbonate concentrations (23.5 mmol/l) from the blood gas analyzer. His serum tCO 2 concentrations remained critically low throughout hospitalization without any evidence of acidosis. Serum tCO 2 levels were measured via Siemens ADVIA Chemistry XPT system.
Results: Mixing studies revealed non-linearity of serum tCO 2 , suggesting the presence of interfering substances. Triglyceride concentrations were normal. Serum electrophoresis revealed a 0.4 mg/dl M-protein. The patient's serum tCO 2 concentrations were repeated on different chemistry analyzer platforms - including Siemens, Roche, and Abbott - which demonstrated that the interference was specific to the Siemens chemistry analyzer. Serum tCO 2 was significantly elevated after ultrafiltration of paraprotein, which confirmed the root cause of pseudohypobicarbonatemia.
Conclusion: Laboratory professionals should be aware that spuriously low serum tCO 2 concentrations may result from unique interfering substances, such as paraproteins, that are both patient- and chemistry analyzer-specific.
(Copyright © 2021. Published by Elsevier B.V.)
Databáze: MEDLINE
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