EKFC cystatin C eGFR (2023) — egfr_ekfc

Estimates GFR from serum cystatin C using the sex- and race-free EKFC cystatin C equation (Pottel et al., 2023).

Usage

egfr_ekfc_cys(cystatin, age, q = NULL)

Arguments

cystatin: Numeric vector of serum cystatin C in mg/L.
age: Numeric vector of age in years.
q: Optional numeric vector of the reference cystatin C Q value (median cystatin C, in mg/L). When NULL (the default) the built-in age-based EKFC reference Q is used; supply a value to use a population- or individual-specific Q. Recycled to the length of the other inputs.

Value

Numeric vector of eGFR in mL/min/1.73m^2.

Reference Q

The default Q is the sex- and race-free value published with the equation: 0.83 mg/L below age 50, and 0.83 + 0.005 * (age - 50) from age 50 onwards. The same value of 0.83 mg/L is endorsed for children (Pottel et al., Pediatr Nephrol. 2024), so no separate paediatric Q is applied.

Validity

Applicable from age 2 years upwards.

References

Pottel H, Bjork J, Rule AD, et al. Cystatin C-based equation to estimate GFR without the inclusion of race and sex. N Engl J Med. 2023;388(4):333-343. doi:10.1056/NEJMoa2203769

Examples

egfr_ekfc_cys(cystatin = 0.9, age = 50)
#> [1] 88.54123
egfr_ekfc_cys(0.9, 50, q = 0.85)
#> [1] 90.96019