To estimate the glomerular filtration rate (GFR)

1. Serum creatinine shall be taken within 24 hours of urine collection

2. 24 hours urine collection for creatinine measurement

Plain tube for serum and universal container for urine.

1. Avoid taking interfering medications as below and should be stopped beforehand if possible:

   • Cephalosporin & aminoglycoside antibiotics

   • Flucytosine

   • Cisplatin

   • Cimetidine

   • Trimethoprim

2. Ensure patient drink sufficient water before start collecting and continue good hydration throughout the collection procedure.

3. A meat free diet is recommended

Label 24 hours urine container with two identifier (Name and identity no - NRIC/MRN)

Day 1:

Instruct the patient to void first urine in the morning and discard the urine. Record date & time collection started.  Then, collect all urine in a 24 hours container for next 24 hours.

(Keep sample in a cool & dry place during the collection period.)

Day 2:

Include the final urine voided into 24 hours urine container. Record date & time completed.

24 hours urine collection result may be associated with significant collection errors, largely due to improper timing and missed samples, leading to over-collection and under-collection.

Laboratory Investigation Guidelines for Chronic Kidney Disease and Utilization of eGFR in adults, October 2012, Ministry of Health Malaysia.