A 24-hour urine specimen is collected to analyze daily excretion of substances like urea and creatinine, check for poisons or drugs, test for tuberculosis or sex hormones. The patient empties their bladder at 8am on two days, discarding the first sample and collecting all urine over the next 24 hours in a sterile bottle and funnel, kept on ice if testing for hormones. This allows measurement of excretion rates to monitor conditions like total parenteral nutrition.

1. TWENTY-FOUR-HOUR-SPECIMENS

2. WHY IT IS DONE
The urine is analysed for:
 Daily excretion of substances e.g urea,
creatinine and vitamin C
 Poisons e.g heavy metals
 Drugs e.g morphine, sulphonamides
 Mycobacterium tuberculosis
 Sex hormones , adrenal and pituitary
glands

3. CONT….
 Estimation of excretion of
radioactive hormones.
 In case of total parenteral
nutrition (TPN) all the urine
collected during 24 hrs is sent
to the laboratory twice a week
to obtain the excretion rate of
urea and electrolytes

4. PREPARATION
 To prevent contamination of the urine, the
bedpan or urinal must be scrupulously clean.
 A woman patient is asked to wash her vulva
before passing the urine, and not to
contaminate the urine with faeces or toilet
paper.
 A large sterile bottle and funnel are covered
with a sterile towel and kept in a safe place
for receiving the urine.

5. PROCEDURE
 The patient is asked to empty
his or her bladder at 8 a.m. on
two successive days. The first
specimen is discarded but all
the urine passed after that,
including the second 8 a.m.
specimen, is poured into the
large sterile means of the
funnel.

6. CONT….
 If the urine is being collected for
the assay of hormones, 10 ml
of concentrated HCl is poured
into the bottle, and during the
period of collection the bottle is
kept in a bucket of ice water
and chips.