Background: Serum 25-hydroxyvitamin D 25(OH)D testing has increased substantially in routine clinical practice, driven by growing awareness of vitamin D’s systemic roles. However, variability in requisition patterns across clinical specialties warrants periodic evaluation to assess diagnostic yield and optimize laboratory utilization. The present study was undertaken to evaluate serum 25(OH)D test requisition patterns and analyze department-wise distribution of results in a tertiary teaching hospital. Materials and Methods: This hospital-based retrospective observational study was conducted in the Department of Biochemistry from June 2021 to June 2023. A total of 287 subjects for whom serum 25(OH)D testing was requested from various outpatient and inpatient departments were included. Estimation was performed using chemiluminescent Microparticle immunoassay (ARCHITECT i1000SR). Results were categorized according to laboratory-defined reference intervals (49.9 ng/mL high). Statistical analysis was performed using SPSS version 16. Results: Among the 287 subjects (52.6% females; 47.4% males), 87.8% had values within reference limits, 1.4% were low, and 10.8% were elevated. The highest testing frequency occurred in 2022 (55.1%). Department-wise analysis revealed that in Medicine (n=136), 83.1% were within reference limits and 16.2% were elevated; in Orthopaedics (n=111), 93.7% were within reference limits; in Dermatology (n=20), 85.0% were normal; and in Casualty (n=20), 90.0% were normal. Low values were infrequently observed across departments. Conclusion: The predominance of results within laboratory-defined reference intervals across specialties suggests widespread incorporation of vitamin D testing into routine clinical evaluation. Departmental variations in elevated values likely reflect supplementation monitoring or specialty-specific clinical indications. Periodic audit of requisition patterns may assist in ensuring rational and evidence-aligned utilization of vitamin D testing in tertiary healthcare settings.
Jankar et al. (Wed,) studied this question.