Reference limits are specific for age and sex. Each laboratory institute has its own reference limits. This function is useful to query a dataset against this database.
lookup_limits(age, sex, table)numeric, patient age.
character/factor, patient sex, has to be the same length as
age.
data.frame, reference table, has to have the columns:
"age", numeric (same units as in age, e.g. days or years, age of 0
matches all ages),
"sex", factor (same levels for male and female as sex and a special level
"both"), "lower" and "upper", numeric for the lower and upper reference
limits. If an "param" column is given the "lower" and "upper" limits for all
different values in "param" is returned. Additional columns are allowed (and
ignored).
matrix, with 2 columns ("lower", "upper") and as many rows as
length(age).
reference <- data.frame(
param = c("albumin", rep("bilirubin", 4)),
age = c(0, 1, 2, 3, 7), # days
sex = "both",
units = c("g/l", rep("µmol/l", 4)), # ignored
lower = c(35, rep(NA, 4)), # no real reference values
upper = c(52, 5, 8, 13, 18) # no real reference values
)
# lookup albumin reference values for 18 year old woman
lookup_limits(
age = 18 * 365.25,
sex = "female",
table = reference[reference$param == "albumin",]
)
#> lower upper
#> albumin 35 52
# lookup albumin and bilirubin values for 18 year old woman
lookup_limits(
age = 18 * 365.25,
sex = "female",
table = reference
)
#> lower upper
#> albumin 35 52
#> bilirubin NA 18
# lookup bilirubin referenc values for infants
lookup_limits(
age = 0:8,
sex = rep(c("female", "male"), 5:4),
table = reference[reference$param == "bilirubin",]
)
#> lower upper
#> bilirubin NA NA
#> bilirubin NA 5
#> bilirubin NA 8
#> bilirubin NA 13
#> bilirubin NA 13
#> bilirubin NA 13
#> bilirubin NA 13
#> bilirubin NA 18
#> bilirubin NA 18