LABORATORY REFERENCE INTERVALS FOR ROUTINELY ANALYZED IRON PROFILE PARAMETERS IN ADULT POPULATION AGED 18-64 YEARS, IN UASIN GISHU COUNTY, KENYA

Abstract

Reference intervals are regarded as golden tools used to guide clinicians to correctly diagnose and monitor diseases, assess patients' responses to therapy, and forecast any probable risk factors. However, reference intervals vary largely across different populations due to multiple factors. To address these issues, the Clinical Laboratory Standards Institute (CLSI) advocates for the use of locally established and verified RIs. The literature on iron profile RIs for adults in Kenya remains scanty, and no known publications or research has been done for the Uasin Gishu population. The interpretation of these results is currently based on the manufacturer’s provided RIs, derived from other regions. This study was aimed at establishing and verifying normal reference intervals for four routinely analyzed iron profile parameters for the adults in Uasin Gishu County, Kenya. The study was a cross-sectional population study and was carried out at Moi Teaching and Referral Hospital, with 290 healthy participants enrolled for the study using the multi-stage sampling technique. Using a fully automated clinical chemistry and immunochemistry analyzer (Cobas 6000 series), the levels of iron and unsaturated iron binding capacity were analyzed using the ferrozine method, while ferritin and transferrin were analyzed based on the immunoturbidimetric method. Reference values were determined by using the non-parametric method at a confidence interval of 95%, this entailed computing the 2.5th and 97.5th percentiles as the lower and upper limits, respectively. Sigma diagnostics method was used for the verification of the established reference intervals. Statistical analysis was performed using IBM SPSS version 23.0. The established reference intervals were as follows: Ferritin: males: 28.41–425.60 ng/mL, females: 11.15–155.87 ng/mL; Iron: males: 8.27–32.02 umol/L, females: 5.21–25.45 umol/L; Transferrin: males: 2.13–4.01 g/L, females, 2.08–4.04 g/L; UIBC: males, 20.50–64.08 umol/L, females: 20.07–64.21 umol/L. Comparisons between genders for significant differences were done using Mann-Whitney U tests, revealing statistically significant differences in ferritin and iron levels with p=<0.001. Conversely, transferrin and UIBC exhibited no significant gender-based differences with p values of 0.829 and 1.00 respectively. Notably, the manufacturer's given RIs were verified, with the majority aligning with the established RIs except for iron values in women. Despite this, the RIs showed a broader interval spread between the upper and lower limits, which is clinically significant. In conclusion, the established reference intervals are sex, and age specific for the adult population in Uasin Gishu County, Kenya. These intervals are crucial for accurate clinical diagnosis and effective patient management.