From donor to diagnosis: using blood banks to estimate MGUS prevalence in a Mexican population Open Access

• MGUS prevalence was 3% in healthy adults aged 50–65 in northeastern Mexico.

• Preliminary evidence suggests MGUS may be more common in this region, underscoring the need for larger studies.

Monoclonal gammopathy of undetermined significance (MGUS) is the most common plasma cell disorder and a known precursor to multiple myeloma (MM) and related conditions. While MGUS precedes virtually all cases of MM, most individuals with MGUS do not progress to malignancy. Its prevalence varies by age, sex, and ethnicity, with lower rates historically reported in Hispanic populations. However, recent evidence suggests MGUS may be underdiagnosed in Mexican individuals. We aimed to determine the prevalence of MGUS in healthy adults aged 50–65 in northeastern Mexico. A cross-sectional study was conducted at a university hospital blood bank between August 2023 and April 2024. Blood donors aged ≥50 years who met eligibility criteria were enrolled. A sample size of 164 participants was calculated based on an estimated 4% prevalence. Serum samples were analyzed using agarose gel electrophoresis and immunofixation. Positive cases were referred for hematologic evaluation. Of the 164 participants (75.6% male), the median age was 54 years (IQR, 52–59). MGUS was detected in five individuals (3.0%; 95% CI, 0.6–6.1%), including four cases identified by both electrophoresis and immunofixation and one by immunofixation alone. The prevalence was 2.3% (95% CI, 0–5.4%) in participants aged 50–59 and 5.7% (95% CI, 0–14.3%) in those aged 60–65. When stratified by sex, prevalence was 3.2% (95% CI, 0.8–6.5%) in men and 2.5% (95% CI, 0–7.5%) in women. Detected monoclonal proteins included IgG kappa, IgA lambda, IgM lambda, and IgG lambda. MGUS prevalence (3%) is consistent with U.S. data and may be higher than prior Mexican estimates, though limited by sample size. Findings suggest underdiagnosis and highlight the need for larger studies.