Laboratory Test Information Guide

Details for Porphyrin Screen and Quantitation, 24-Hour Urine

Test Name: Porphyrin Screen and Quantitation, 24-Hour Urine
Alternate Name(s): Uroporphyrin III
Heptacarboxylic acid
Hexacarboxylic acid
Pentacarboxylic acid
Coproporphyrin I
Coproporphyrin III
Laboratory: Core
Specimen Type: 24-hour urine collected with 5 g sodium carbonate. Containers with appropriate additives are obtained from the Core Laboratory.
Collection Information: Collection of 24-Hour Urine Sample

Please complete the laboratory label attached to the collection bottle to include patient’s name, collection start time and date, and collection end time and date.

This collection is not suitable for ALA/PBG testing. See “Porphyrin Precursors” for ALA/PBG testing.
Test Schedule: Referred out Monday-Thursday
Turnaround time from when specimen
is received in testing laboratory:
10 days
Reference Range: Reference Range Screen: Normal

Uroporphyrin III: ≤20 nmol/d
Heptacarboxylic acid: ≤16 nmol/d
Hexacarboxylic acid: ≤2 nmol/d
Pentacarboxylic acid: ≤2 nmol/d
Coproporphyrin I: 5-90 nmol/d
Coproporphyrin III: 15-242 nmol/d
Copro III/Copro I ratio: 2.6-5.3

Interpretation provided on report.

Reference intervals are for adults only and are not available for individuals 17 years of age or younger.
Effective Date: 2003-07-08
Revised Date: 2021-06-29
Critical Value:  
Interpretive Comments:  
Special Processing: Transfer an aliquot of at least 20 mL of the measured urine to a sterile container. Final pH should be 7-10. Keep aliquot protected from light. If wrapped with foil, specimen must be labelled inside and outside of the light-protecting wrap. Store and ship urine aliquot frozen. Indicate the 24-hour total volume (in L) and collection date.
Comments: Screen will be performed first. Quantitation will automatically be performed (and billed) if preliminary screen is positive.
Method of Analysis: Spectrophotometry and HPLC
Critical Information Required:  
Storage & Shipment: Store and ship urine aliquot frozen and protected from light.
System Codes: 
Referred To: In-Common Laboratories

Questions? Comments? Contact Laura Gopaul