Background Objective laboratory cues that suggest harmful alcohol intake can be useful in routine General Medicine practice, where history may be incomplete or under-reported. Objectives To evaluate mean corpuscular volume (MCV) as a biomarker of alcohol consumption and compare its performance with liver enzyme markers (GGT, AST, ALT) across alcohol-intake categories. Methods A hospital-based observational study of 100 participants was analysed. Alcohol intake (g/day), duration of use (years), MCV (fL), and liver enzymes (GGT, AST, ALT) were compared across three categories (non-drinker, social drinker, heavy drinker) using descriptive statistics and one-way ANOVA. Pearson correlation and linear regression assessed the relationship between alcohol intake and MCV. ROC analysis evaluated diagnostic performance of MCV for identifying the ‘heavy’ category. Results Of 100 participants, 50 were categorized as heavy drinkers, 30 as social drinkers, and 20 as non-drinkers. Mean MCV increased across categories (non-drinker: 85.92 ± 1.25; social: 90.41 ± 1.49; heavy: 102.22 ± 2.19; ANOVA p<0.001). Alcohol intake showed a strong positive correlation with MCV (r=0.992, p<0.001). In ROC analysis, an MCV cutoff of ≥98.6 fL identified the heavy category with AUC=1.000 and 100% sensitivity and specificity within the study cohort. Conclusion In this study, MCV rose sharply with increasing alcohol intake and showed excellent discrimination for the heavy-drinking category. Interpretation should still account for alternative causes of macrocytosis and local clinical context.

Mean Corpuscular Volume; Alcohol Consumption; Macrocytosis; Gamma-Glutamyltransferase; Liver Enzymes; Biomarker