Skip to contents

Kynurenine/Tryptophan Ratio (KTR)

Source: R/kyn_trp_ratio.R
kyn_trp_ratio.Rd

Computes the ratio of kynurenine to tryptophan, a marker of IDO activity and immune activation.

Usage

kyn_trp_ratio(
  data,
  col_map = list(kynurenine = "Kyn_nM", tryptophan = "Trp_uM"),
  na_action = c("keep", "omit", "error", "ignore", "warn"),
  check_extreme = FALSE,
  extreme_action = c("warn", "cap", "error", "ignore", "NA"),
  extreme_rules = NULL,
  verbose = FALSE
)

Arguments

data

A data.frame or tibble with kynurenine and tryptophan concentrations.

col_map

Named list with:

  • kynurenine: column for kynurenine (nmol/L)

  • tryptophan: column for tryptophan (mumol/L)

na_action

One of c("keep","omit","error","ignore","warn").

check_extreme

Logical; if TRUE, scan inputs for plausible ranges.

extreme_action

One of c("warn","cap","error","ignore","NA").

extreme_rules

Optional overrides; defaults: list(kynurenine_nmolL = c(100, 20000), tryptophan_umolL = c(10, 150), ratio = c(0, 200)).

verbose

Logical; if TRUE, emits progress via rlang::inform.

Value

A tibble with one column: kyn_trp_ratio (numeric).

Details

KTR is calculated as Kyn (nmol/L) divided by Trp (mumol/L). Elevated KTR indicates increased tryptophan catabolism via the kynurenine pathway, often reflecting inflammation and cell-mediated immune activation.

Inputs should already be in Kyn (nmol/L) and Trp (mumol/L).

References

Fuchs D, Moller AA, Reibnegger G, Werner ER, Werner-Felmayer G, Dierich MP, Wachter H (1998). “Serum kynurenine-to-tryptophan ratio increases with disease progression in HIV-1 infection.” Clinical Chemistry, 44(4), 858–862. doi:10.1093/clinchem/44.4.858 , PMID:9555676. ; Damerell V, Midttun O, Ulvik A, et al. (2025). “Circulating tryptophan-kynurenine pathway metabolites are associated with all-cause mortality among patients with stage I–III colorectal cancer.” International Journal of Cancer, 156(3), 552–565. doi:10.1002/ijc.35183 .

Examples

df <- data.frame(Kyn_nM = c(2500, 3100, 2700), Trp_uM = c(55, 48, 62))
kyn_trp_ratio(df)
#> # A tibble: 3 × 1
#>   kyn_trp_ratio
#>           <dbl>
#> 1          45.5
#> 2          64.6
#> 3          43.5