Laboratory reference values for healthy adults from southern Tanzania

Objectives: To define and discuss reference ranges for commonly determined laboratory parameters in healthy adults from southern Tanzania. Methods: A population-based sample of adult volunteers from Mbeya, Tanzania, who were not HIV positive or showing signs and symptoms of other diseases, participated in this study. We enrolled 145 women and 156 men between 19 and 48 years of age to determine clinical chemistry (CC), haematology and lymphocyte immunophenotyping (LIP) parameters using standard laboratory methods. Medians and nonparametric 95% reference ranges for each parameter were determined and compared with reference ranges from the USA, Europe and from other African countries. Results: Agreement with ranges from developed countries was poor: for CC values the average concordance was 80.9% and 86.7% with values from two developed countries. Haematology ranges from the USA classified 86.3% of values correctly, whereas ranges from three different sub-Saharan Africa (SSA) sites classified between 82.5% and 94.5% of values correctly. The agreement of LIP reference ranges was 87.5% with values determined in Germany but between 91.7% and 95.8% compared with values determined at other sites in SSA. Conclusion: Clinical reference ranges determined in developed countries are inadequate for use in SSA. Laboratories in this region should either define their own or use values determined under similar conditions. The ranges reported here are more appropriate for use in SSA than ranges determined in developed countries.