Vectorised function to convert UKKDRI values to quartiles of risk. The function takes a numeric vector of UKKDRI values as input, and returns a vector of quartiles. By default this is also a numeric vector with values 1-4, but this can be changed to a character string vector of D1-D4 to match the nomenclature in the NHSBT ODT documentation by setting the prefix parameter to TRUE. The output can also be as a vector of factors by setting fct to TRUE (this can be combined with the prefix parameter).

ukkdri_q(dri, prefix = FALSE, fct = FALSE)



numeric vector of UKKDRI values


whether to prefix results with "D" (default FALSE)


whether to return results as a factor (default FALSE)


vector of UKKDRI quartiles


The UK KDRI quartile ranges are documented in the UK kidney matching policy which can be found on the NHS Blood & Transplant ODT website at


# obtain quartile of a single value ukkdri_q(1.01)
#> [1] 2
# factor vector of results with prefix dri = c(0.69, 1.01, 1.36, 1.54) ukkdri_q(dri, prefix = TRUE, fct = TRUE)
#> [1] D1 D2 D3 D4 #> Levels: D1 D2 D3 D4