Spurious test results as a diagnostic clue – pseudohyponatremia revealing multiple myeloma

This case highlights the importance of artifacts in laboratory measurement, in this case recognizing analytical interferences when discordant hyponatremia is found. Confirmatory testing by direct potentiometry ion-specific electrodes prevents misdiagnosis and inappropriate therapy. Early identification of pseudohyponatremia further emphasizes the crucial role of the laboratory in ensuring accurate interpretation and optimizing patient management.