A Single Center Study Investigating Clinical Outcomes of Testing for Multiple Myeloma and Immune Deficiency at Low Globulin Levels.

Background: Both primary (e.g. common variable immune deficiency, CVID) and secondary immune deficiency as well as multiple myeloma (MM) require medical intervention and treatment delay can exacerbate morbidity. This study investigated the potential importance of low levels of calculated globulin to detect immune deficiency and MM associated with immunoparesis (light chain, non-secretory MM). Methods: One hundred and thirty-nine patient serum samples from community physicians and outpatient clinics for liver function tests with low calculated globulin (<16 g/L, RR 18-37 g/L) levels were screened for immunoglobulins and protein electrophoresis. Further, 110 patients with globulin levels ≤16 g/L with screening for immunoglobulin levels and protein electrophoresis, requested through routine clinical care, were included in the analysis. Results: Approximately 47% of patients in this cohort had secondary antibody deficiency as a result of hematological malignancy. Secondary iatrogenic (immunosuppressants, antiepileptic drugs) immune deficiency was detected in 20% of patients and a significant percentage of the patients were found by reflex testing at globulin levels <16 g/L. During the study period the screening detected new light chain and non-secretory MM in 2.2% of patients. Three patients with CVID and six patients with light chain myeloma were previously detected by screening, consequently alerting clinicians and reducing delay in treatment. A further 23% with several co-morbid conditions showed unexpected hypogammaglobulinemia; in this category, the study identified a subgroup that required further investigation. Conclusion: Investigation of low globulin levels detects patients with primary and secondary immune deficiency and MM. Optimizing treatment for decreased immunoglobulins in patients with other clinical co-morbidities may require increased clinician awareness and watchful clinical and laboratory assessment.