CITRATE, URINE - 24 HOUR

Test Documentation
Specimen Required
Collect urine following collection instructions below. Send 25.0 mL urine (10.0 mL minimum) refrigerated in a screw-capped plastic urine container. Record total volume on requisition and specimen label.
24 HOUR URINE COLLECTION: The bladder must be emptied at the time the collection is to begin, and this urine is discarded. Thereafter all urine must be collected until the end of the scheduled time, and kept refrigerated during collection.
Preferred method of collection for 24 hour collection: Collect urine with 10 grams of boric acid at the start of collection. Refrigerate urine during collection (critical). Mix the collection well before checking the pH and ensure boric acid tablet is well dissolved. pH should be between 4-7. Send 25.0 mL urine (10.0 mL minimum) refrigerated in a screw-capped plastic urine container. Record total volume on requisition and specimen label.

Alternate Specimen
Refrigerate urine during collection (critical) and add 10 grams of boric acid to the entire collection within 4 hours of completing. Mix the collection well before checking the pH and ensure that boric acid tablet is well dissolved. pH should be between 4-7. Record total volume on both the requisition and specimen label. Send refrigerated 25.0 mL aliquot (10 mL minimum) refrigerated in a screw-capped plastic urine container.

Rejection Criteria
Samples with incorrect pH

Methodology
Spectrophotometry

Stability
Room Temperature: Unacceptable; Refrigerated: 14 days; Frozen: 2 months

Reference Range
Citrate 24 hr Urine:   280-1240 mg/24 hr  
Creatinine 24 hr Urine:   Males: 1-2 g/24 hr  
   Females: 0.8-1.8 g/24 hr  

Performed
Monday, Wednesday, Friday

Turnaround Time3-4 days
Test CodeUCI24
CPT-4 Code (s)
82507, 82570
LOINC Codes
Citrate, urine   6687-8  
Creatinine   2162-6  
Total volume   19153-6  
Hours collected   30211-7  

Warde
Medical
Laboratory