Reference intervals for 33 biochemical analytes in healthy Indian population: C-RIDL IFCC initiative

Abstract

Background In 2011, the IFCC Committee on Reference Intervals and Decision Limits (C-RIDL) initiated a worldwide multicenter study on references values facilitating the implementation of country-specific reference intervals (RIs). There has been no well-designed RI study in India. This study aims to derive RIs for 33 major biochemical analytes in carefully selected healthy Indians as defined in C-RIDL protocol. Methods A total of 512 healthy Indians were recruited. Sera collected from overnight fasting blood samples were measured collectively for the analytes. Multiple regression analysis (MRA) and nested analysis of variance (ANOVA) were used to identify the potential sources of variation (SV) of test results. RI were derived by both parametric and non-parametric methods for comparison. The need for secondary exclusion by latent abnormal values exclusion (LAVE) method was examined. Results MRA results indicated that both age and BMI were apparent SV for many analytes in both sexes. ANOVA revealed that partition of RIs by gender and age was required for 17 analytes (TC, HDL-C, TG, hsCRP, ALB, AST, ALT, ALP, GGT, TBil, Urea, CRE, UA, Fe, TTR, CK and IgM) and 5 (Glu, ALB, TC, ALP and Urea), respectively. RIs by parametric method were generally narrower than by non-parametric method, reflecting distorted peripheral distributions of test results. The LAVE method had no appreciable effect on RIs possibly due to inconsistency among abnormal values of related analytes. Conclusions This study has for the first time provided comprehensive RIs information in healthy Indians. The final RIs adopted were those derived by parametric method without LAVE procedure.

Determination of reference intervals for common chemistry and immunoassay tests for Kenyan adults based on an internationally harmonized protocol and up-to-date statistical methods

“…were similar to published reports from Saudi Arabia and Turkey [12,13], our TBil RI of 6--43 μmol/L for males and 5-27 μmol/L for females is almost double what has been reported in published studies from outside the African continent as shown in S2 Table [2,[12][13][14][15]. We hypothesize that Gilbert's syndrome, the commonest genetic cause of asymptomatic unconjugated hyperbilirubinaemia, could be quite prevalent in our population.…”

“…Our RIs for immunoglobulins are higher than those derived in the US but very similar to those derived in India [2,15]. Karita et al also found high levels of IgG in several SSA countries PLOS ONE Table 5.…”

“…Ichihara et al in a similar study carried out in Asia found that the closer the country or region was to the equator, the higher the serum concentrations of positive inflammatory markers (IgG, C3, CRP) a phenomenon they ascribed to increased exposure to infectious agents [23]. Similar to the IFCC study in India, IgM was significantly higher in female participants requiring the determination of sex specific RIs [15]. We hypothesize that this could be linked to the role that estrogen plays in enhancing humoral immunity [24].…”

Reference intervals for 26 common biochemical analytes in term neonates in Jilin Province, China

“…The variations of between-delivery-mode, between-sex and between-day-age components were expressed as SDR-dm, SDR-sex and SDR-age respectively. A ratio greater than 0.40 was considered as the criterion to partition RIs, in order to reduce bias caused by a narrow measure of between-individual variation [1,23]. According to CLSI EP28-A3c guidelines [16], the lower limits (LL) and upper limits (UL), referring to 2.5th percentiles and 97.5th percentiles, were derived by the nonparametric method or robust method after deciding the partition.…”

Age- and Sex-Specific Reference Intervals for Myocardial Enzyme Activity in Healthy Chinese Han Population Aged 1∼<18 years

“…Research studies find [2][3][4][5] RIs are with variety of factors involved such as race, region, ethnicity, diet, and so on. For example, Wu et al [6] found that lower limit of the platelet interval in Chinese Han adults was slightly lower than that of the peer group in the United States [7] and Malaysia [8], and RIs of white blood cell count and neutrophil count were lower than those of the homologous US population [7] while higher than those of the Africans [9]; Oliver's research [10] showed that RIs of certain biochemical indicators of the aged living in Asmara, Eritrea, were higher than those of Caucasians and lower than those of South Africans.…”