Analytical interference by IgM paraprotein causing platform-dependent electrolyte discrepancies: a case-based laboratory investigation.
Sheng Wang, Xiaoyong Duan, Yulin Zou et al.
✦ AI-curated · Sources linked
Case in brief
An 85-year-old man presented with low back pain, and laboratory tests revealed significant discrepancies in serum electrolyte and calcium measurements between two platforms. The Hitachi platform indicated severe hypercalcemia and hyponatremia, while the Beckman Coulter AU platform showed only mild abnormalities. Further investigation identified IgM paraprotein interference as the cause, leading to a diagnosis of Waldenström macroglobulinemia.
What made this case unusual
The case illustrates marked inter-platform discordance in electrolyte measurements due to IgM paraprotein interference, with a 71.3% difference in total calcium results despite both platforms employing the same analytical method.
Diagnostic / clinical pearl
Clinicians should be aware that analytical discrepancies in electrolyte measurements may indicate underlying conditions, necessitating further investigation to rule out interference from monoclonal proteins.
Why it matters
This case underscores the importance of method comparison in laboratory diagnostics, particularly when faced with unexpected biochemical results that could mask serious underlying diseases.