~ 47 ~ ISSN Print: 2617-4693 ISSN Online: 2617-4707 IJABR 2017; 1(1): 47-57 www.biochemjournal.com Received: 12-01-2017 Accepted: 21-03-2017 Richard M Gitimu a) Department of Biochemistry, Microbiology and Biotechnology, School of Pure and Applied Sciences, Kenyatta University, P.O Box 43844 00100, Nairobi, Kenya b) Department of Laboratory Medicine, Taita Taveta University, P.O Box 635-80300 Voi, Kenya Joseph K Gikunju Department of Medical Laboratory Sciences, Jomo Kenyatta University of Agriculture and Technology, P.O Box 62000-00100 Nairobi. Stanley K Waithaka Department of Medical laboratory Sciences, Mount Kenya University, P.O Box 342-01000 Thika, Kenya Eliud NM Njagi Department of Biochemistry, Microbiology and Biotechnology, School of Pure and Applied Sciences, Kenyatta University, P.O Box 43844 00100, Nairobi, Kenya. Corresponding Author: Richard M Gitimu a) Department of Biochemistry, Microbiology and Biotechnology, School of Pure and Applied Sciences, Kenyatta University, P.O Box 43844 00100, Nairobi, Kenya b) Department of Laboratory Medicine, Taita Taveta University, P.O Box 635-80300 Voi, Kenya Thyroid profile reference limits and normal values for adult and geriatric population of Taita-taveta County, Kenya Richard M Gitimu, Joseph K Gikunju, Stanley K Waithaka and Eliud NM Njagi DOI: https://doi.org/10.33545/26174693.2017.v1.i1a.118 Abstract Reference interval limits for thyronine (TSH), thyroxine (T4) and triiodothyronine (T3) for geriatrics of the world including those of geriatrics of Taita-Taveta County, Kenya are limited. The aim of this study was to develop the 95% reference interval limits for thyronine (TSH), total thyroxine (T4), and total triiodothyronine (T3) for adults and geriatrics of Taita-Taveta County, Kenya. Two hundred and forty four referent individual randomly recruited from the four sub-county of Taita Taveta (Mwatate, Wundanyi, Voi and Taveta) County, Kenya participated in this reference interval limits development study. These referents had no history of thyroid gland diseases, were not on medication for thyroid diseases, and medications that affect the hypothalamus-pituitary-thyroid gland axis. These referents were free from HIV/ AIDS, syphilis, hepatitis B and C, and pregnancy. The serum used for the measurement of thyronin (TSH), total tetraiodothyronine (thyroxine [T4]) and triiodothyronine (T3) was obtained from blood which had been drawn from the vein of the 244 referent participants between 7-10 am after 8 to 12 hours of fasting recruited between May 2015 and December 2017. TSH, T4 and T3 were measured on a quality controlled calibrated Chemwell Auto-Analyzer machine using the principle that combines an enzyme immunoassay sandwich method with a final fluorescent detection (enzyme linked fluorescent assay (ELFA)) at the Clinical Chemistry Laboratory, Taita-Taveta Sub County Hospital, Voi, Kenya. The reference interval limits for the measured analytes was based on the median and 2.5 percentile and 97.5 percentile. The developed reference interval limits for TSH, T4 and T3 were 0-6 mU/L, 2-15 nmol/L and 0-4 nmol/L, respectively. There were significant age and sex related differences in T4. The developed reference interval limits for TSH, T4 and T3 differed from those reported in reagents manufacturer kits and literature. This study has established age and gender dependent 95% reference intervals for TSH, T4 and T3 that differ from those reported in literature. Each clinical laboratory therefore needs to develop their own reference intervals using their local healthy population for these analytes for accurate diagnosis and effective medical care for patients suffering from thyroid gland related diseases. Keywords: tetraiodothyronine, Taita-Taveta, Wundanyi Introduction Clinical chemistry reference interval is the interval between, and including, two reference limits; the lower 2.5 percent and upper 97.5 percent limits. Reference intervals for thyroid hormones are developed using a minimum of 120 healthy referent individuals selected on the basis of meeting a specific exclusion and inclusion criteria and covering 95% of the healthy referent individuals. If the referent individuals are stratified by age and sex, each age category require a minimum of 120 individuals for each gender (Horowitz et al., 2010) [10] . Reference interval for thyroid stimulating hormone (TSH), total triiodothyronine (T3), free triiodothyronine (fT3), total thyroxine (T4), and free thyroxine (fT4) are biochemical markers that are commonly used for clinical diagnosis of thyroid function disorders. The thyroid function disorders include graves’ disease, thyroid nodule (toxic autonomously functioning thyroid nodule or toxic multinodular goitre), thyroiditis, and excess iodine from some medicines which cause hyperthyroidism, and hashimoto’s t hyroiditis, iodine deficiency and non-functioning thyroid gland that cause hypothyroidism (Musa et al. 2018; Ali et al., 2018) [16, 1] . International Journal of Advanced Biochemistry Research 2017; 1(1): 47-57