Computes:
sweat_chloride (mmol/L)
Na_K_ratio (sweat Na+/K+)
sweat_lactate (mmol/L)
sweat_rate (L/m^2/h) from body mass loss per hour per m^2
Usage
sweat_markers(
data,
col_map = NULL,
verbose = TRUE,
na_action = c("keep", "omit", "error"),
na_warn_prop = 0.2
)Arguments
- data
A data.frame or tibble containing sweat assay and anthropometrics.
- col_map
Named list mapping required inputs (defaults assume same names):
sweat_chloride, sweat_Na, sweat_K, sweat_lactate, weight_before, weight_after, duration, body_surface_area
- verbose
Logical; if
TRUE, prints progress messages and a completion summary.- na_action
One of
c("keep","omit","error")for handling missing values in required inputs. Default "keep".- na_warn_prop
Proportion \([0,1]\) to trigger high-missingness diagnostics for required inputs (debug level). Default 0.2.
Details
Inputs are validated, missingness handled via na_action, safe divisions
are used to avoid Inf/NaN, and an optional extremes scan/cap is available.
Expected units:
sweat_chloride, sweat_Na, sweat_K: mmol/L
sweat_lactate: mmol/L
weight_before, weight_after: kg
duration: hours
body_surface_area: m^2
Note
sweat_chloride and sweat_lactate are pass-through columns; no formula
is applied. Na_K_ratio is a simple Na/K division. sweat_rate uses the
mass-loss method: (weight_before - weight_after) / duration / body_surface_area
(units: L/m²/h; assumes 1 kg \(\approx\) 1 L).
Dill & Costill 1974 describes haematocrit-based blood-volume change, not sweat
rate directly; cited here as background context only.
References
Gibson LE, Cooke RE (1959). “A test for concentration of electrolytes in sweat in cystic fibrosis of the pancreas utilizing pilocarpine by iontophoresis.” Pediatrics, 23(3), 545–549. (pilocarpine sweat chloride test origin; background) Dill DB, Costill DL (1974). “Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration.” Journal of Applied Physiology, 37(2), 247–248. doi:10.1152/jappl.1974.37.2.247 . (dehydration and fluid loss context; background) Farrell PM, White TB, Ren CL, Hempstead SE, Accurso F, Derichs N, Howenstine M, McColley SA, Rock M, Rosenfeld M, Sermet-Gaudelus I, Southern KW, Marshall BC, Sosnay PR (2017). “Diagnosis of cystic fibrosis: consensus guidelines from the Cystic Fibrosis Foundation.” Journal of Pediatrics, 181S, S4–S15.e1. doi:10.1016/j.jpeds.2016.09.064 . (CF diagnostic sweat chloride cutoffs; background) Sawka MN, Cheuvront SN, Kenefick RW (2015). “Hypohydration and human performance: impact of environment and physiological mechanisms.” Sports Medicine, 45(Suppl 1), S51–S60. doi:10.1007/s40279-015-0395-7 . (sweat rate and hypohydration context; background)
Examples
df <- tibble::tibble(
sweat_chloride = 45,
sweat_Na = 55,
sweat_K = 5,
sweat_lactate = 4.8,
weight_before = 70.0,
weight_after = 69.5,
duration = 1.0,
body_surface_area = 1.9
)
sweat_markers(df)
#> sweat_markers(): reading input 'df' — 1 rows × 8 variables
#> sweat_markers(): col_map (8 columns — 8 inferred from data)
#> sweat_chloride -> 'sweat_chloride' (inferred)
#> sweat_Na -> 'sweat_Na' (inferred)
#> sweat_K -> 'sweat_K' (inferred)
#> sweat_lactate -> 'sweat_lactate' (inferred)
#> weight_before -> 'weight_before' (inferred)
#> weight_after -> 'weight_after' (inferred)
#> duration -> 'duration' (inferred)
#> body_surface_area -> 'body_surface_area' (inferred)
#> sweat_markers(): computing markers:
#> sweat_chloride [sweat_chloride]
#> Na_K_ratio [sweat_Na, sweat_K]
#> sweat_lactate [sweat_lactate]
#> sweat_rate [weight_before, weight_after, duration, body_surface_area]
#> sweat_markers(): results: sweat_chloride 1/1, Na_K_ratio 1/1, sweat_lactate 1/1, sweat_rate 1/1
#> # A tibble: 1 × 4
#> sweat_chloride Na_K_ratio sweat_lactate sweat_rate
#> <dbl> <dbl> <dbl> <dbl>
#> 1 45 11 4.8 0.263