Geoffrey Omuse1,2, Kiyoshi Ichihara3, Daniel Maina1, Mariza Hoffman4, Elizabeth Kagotho1, Alice Kanyua5, Jane Mwangi6, Caroline Wambua6, Angela Amayo7, Peter Ojwang8, Zul Premji9, Rajiv Erasmus2. 1. Department of Pathology, Aga Khan University, Nairobi, Kenya. 2. Division of Chemical Pathology, Department of Pathology, Stellenbosch University, Cape Town, South Africa. 3. Faculty of Health Sciences, Yamaguchi University Graduate School of Medicine, Ube, Japan. 4. Chemical Pathology, Pathcare, Cape Town, South Africa. 5. Nairobi Hospital, Nairobi, Kenya. 6. Pathcare, Nairobi, Kenya. 7. Department of Pathology, University of Nairobi, Nairobi, Kenya. 8. Department of Pathology, Maseno University, Maseno, Kenya. 9. Formerly of Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
Abstract
BACKGROUND: Due to a lack of reliable reference intervals (RIs) for Kenya, we set out to determine RIs for 40 common chemistry and immunoassay tests as part of the IFCC global RI project. METHODS: Apparently healthy adults aged 18-65 years were recruited according to a harmonized protocol and samples analyzed using Beckman-Coulter analyzers. Value assigned serum panels were measured to standardize chemistry results. The need for partitioning reference values by sex and age was based on between-subgroup differences expressed as standard deviation ratio (SDR) or bias in lower or upper limits (LLs and ULs) of the RI. RIs were derived using a parametric method with/without latent abnormal value exclusion (LAVE). RESULTS: Sex-specific RIs were required for uric acid, creatinine, total bilirubin (TBil), total cholesterol (TC), ALT, AST, CK, GGT, transferrin, transferrin saturation (TfSat) and immunoglobulin-M. Age-specific RIs were required for glucose and triglyceride for both sexes, and for urea, magnesium, TC, HDL-cholesterol ratio, ALP, and ferritin for females. LAVE was effective in optimizing RIs for AST, ALT, GGT iron-markers and CRP by reducing influence of latent anemia and metabolic diseases. Thyroid profile RIs were derived after excluding volunteers with anti-thyroid antibodies. Kenyan RIs were comparable to those of other countries participating in the global study with a few exceptions such as higher ULs for TBil and CRP. CONCLUSIONS: Kenyan RIs for major analytes were established using harmonized protocol from well-defined reference individuals. Standardized RIs for chemistry analytes can be shared across sub-Saharan African laboratories with similar ethnic and life-style profile.
BACKGROUND: Due to a lack of reliable reference intervals (RIs) for Kenya, we set out to determine RIs for 40 common chemistry and immunoassay tests as part of the IFCC global RI project. METHODS: Apparently healthy adults aged 18-65 years were recruited according to a harmonized protocol and samples analyzed using Beckman-Coulter analyzers. Value assigned serum panels were measured to standardize chemistry results. The need for partitioning reference values by sex and age was based on between-subgroup differences expressed as standard deviation ratio (SDR) or bias in lower or upper limits (LLs and ULs) of the RI. RIs were derived using a parametric method with/without latent abnormal value exclusion (LAVE). RESULTS: Sex-specific RIs were required for uric acid, creatinine, total bilirubin (TBil), total cholesterol (TC), ALT, AST, CK, GGT, transferrin, transferrin saturation (TfSat) and immunoglobulin-M. Age-specific RIs were required for glucose and triglyceride for both sexes, and for urea, magnesium, TC, HDL-cholesterol ratio, ALP, and ferritin for females. LAVE was effective in optimizing RIs for AST, ALT, GGTiron-markers and CRP by reducing influence of latent anemia and metabolic diseases. Thyroid profile RIs were derived after excluding volunteers with anti-thyroid antibodies. Kenyan RIs were comparable to those of other countries participating in the global study with a few exceptions such as higher ULs for TBil and CRP. CONCLUSIONS: Kenyan RIs for major analytes were established using harmonized protocol from well-defined reference individuals. Standardized RIs for chemistry analytes can be shared across sub-Saharan African laboratories with similar ethnic and life-style profile.
Authors: Valentine Sing'oei; Jew Ochola; John Owuoth; June Otieno; Eric Rono; Ben Andagalu; Lucas Otieno; Chiaka Nwoga; Nathanial K Copeland; John Lawlor; Adam Yates; Michelle Imbach; Trevor A Crowell; Leigh Anne Eller; Edwin Kamau; Kayvon Modjarrad; Jessica Cowden; Julie Ake; Merlin L Robb; Christina S Polyak Journal: PLoS One Date: 2021-03-30 Impact factor: 3.240