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Table 2 Reference intervals for serum cystatin C by age and sex

From: Reference intervals for serum cystatin C and serum creatinine in an adult sub-Saharan African population

Age (years) N = 381 Serum cystatin C (mg/L)
Median (IQR) 2.5th percentile (90%CI) 97.5th percentile (90%CI) p
< 20 Male: 9 0.9 (0.85–1.05) 0.7 (0.70–0.90) 1.1 0.003
Female: 14 0.75 (0.70–0.80) 0.6 (0.60–0.70) 0.9
All: 23 0.8 (0.70–0.90) 0.6 (0.60–0.70) 1.1
[20–30] Male: 95 0.9 (0.80–1.0) 0.6 (0.60–0.70) 1.1 (1.10–1.10) < 0.001
Female: 89 0.7 (0.70–0.80) 0.6 (0.50–0.60) 1.0 (0.90–1.00)
All: 184 0.8 (0.70–0.90) 0.6 (0.60–0.60) 1.1 (1.10–1.10)
[30–40] Male: 40 0.9 (0.80–0.90) 0.7 (0.70–0.80) 1.0 (1.00–1.00) 0.001
Female: 31 0.8 (0.60–0.80) 0.5 (0.50–0.50) 1.0
All: 71 0.8 (0.80–0.90) 0.5 (0.50–0.58) 1.0 (1.00–1.00)
[40–50] Male: 32 0.9 (0.80–0.98) 0.7 (0.70–0.70) 1.1 0.002
Female: 21 0.8 (0.70–0.90) 0.6 (0.60–0.70) 1.0
All: 53 0.8 (0.80–0.90) 0.6 (0.60–0.70) 1.0 (1.00–1.00)
≥ 50 Male: 18 1.0 (0.88–1.0) 0.7 (0.70–0.80) 1.2 0.125
Female: 32 0.9 (0.80–0.90) 0.6 (0.60–0.80) 1.1
All: 50 0.9 (0.80–1.00) 0.7 (0.60–0.73) 1.2 (1.10–1.20)
  1. CI confidence interval, IQR interquartile range. Some 90% confidence intervals are not presented due to the small number of participants in corresponding age groups. The Mann-Whitney U-test was used to compare the distribution of serum cystatin C values between males and females. The difference between age-groups was significant when using the Kruskal-Wallis H-test (p < 0.001)