Pool vs Single Sample Determination of Serum Prolactin to Explore Venipuncture-Associated Stress-Induced Variation
Stress triggers transient hyperprolactinemia, yet venipuncture itself induces stress in patients. This study investigated the association between venipuncture-induced stress and serum prolactin elevation.
Transient hyperprolactinemia is a well-documented phenomenon often attributed to physiological stress responses. In clinical laboratory settings, venipuncture serves as a significant source of such stress, potentially confounding diagnostic accuracy for prolactin levels. Understanding this variation is critical for metabolic research and endocrine diagnostics, where precise measurement of serum prolactin is essential for distinguishing pathological hyperprolactinemia from transient elevations caused by procedural stress.
The researchers conducted a cross-sectional observational study involving 150 outdoor patients visiting a tertiary care hospital. The methodology involved serial sampling through single venipuncture to draw venous blood at distinct time intervals—specifically at 0, 30, and 60 minutes post-venipuncture—to measure serum prolactin levels. The study was executed in two phases, with Phase 1 comparing immediate samples against pooled samples prepared from the three time points, while Phase 2 expanded the analysis to include individual measurements alongside averages and pools.
Statistical analysis revealed a significant decrease in mean prolactin concentrations when using pooled serum samples compared to those collected at the initial 0-minute mark. In Phase 1, the mean prolactin dropped from 19.67 ± 27.69 ng/mL in Group 1 (0 min) to 17.99 ± 24.76 ng/mL in the pooled Group 5. Similarly, Phase 2 demonstrated a reduction from 21.06 ± 25.06 ng/mL in Group 1 to 19.61 ± 23.42 ng/mL in the pooled Group 5, with p-values of 0.0003 and 0.02 respectively indicating statistical significance. Notably, no significant difference was observed between the pooled samples and the average prolactin calculated from individual testing across the three time intervals.
These findings suggest that venipuncture-triggered fear and apprehension can result in transient hyperprolactinemia, which may be mitigated by pooling samples collected at different time points. The study concludes that measuring the analyte from pooled serum is a more efficient alternative to performing multiple tests on individual samples collected at varying intervals. This approach conserves both laboratory resources and patient visitation time while maintaining analytical accuracy for research purposes.