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Porphyrins, 24-Hour Urine Quantitative

Test Codes

EPIC: LAB6269, Beaker: XPOUR, Mayo: PQNU

Department

Send Outs

Instructions

• Please refer to the Specimen Collection Manual for instructions on 24-Hour Urine Collection:
  • Urine 24-Hour Collection - Inpatient
  • Urine 24-Hour Collection - Outpatient
  • Urine 24-Hour Collection - Outreach

Specimen Collection Criteria

Collect: 24-hour urine sample with 5g sodium carbonate preservative.

• Add 5 g of sodium carbonate (T272) as preservative at start of collection. This preservative is intended to achieve a pH of >7.
• Do not substitute sodium bicarbonate for sodium carbonate.
• Keep 24-hour urine specimen iced or refrigerated during collection.
• Include start and end dates and times for the collection period on the specimen container.
• Protect specimen from light during and after collection.

Urine Preservative Options
No Preservative	6N Hydrochloric Acid	Boric Acid (10g)	Sodium Carbonate	50% Acetic Acid
Unacceptable	Unacceptable	Unacceptable	REQUIRED	Unacceptable

Physician Office/Draw Specimen Preparation

Protect specimen from light. Maintain specimens refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Entire preserved 24-hour urine collection, refrigerated (2-8°C or 36-46°F).

Rejection Criteria

• Random urine specimens.
• Specimens not collected and processed as indicated.

In-Lab Processing

Protect specimen from light. Measure total volume of 24-hour urine specimen. Record total volume and collection start and end dates and times in the LIS system. Aliquot 20 mL from the well-mixed 24-hour urine collection and freeze (-20°C/-4°F or below) in a light protected container. (Minimum: 15 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): unacceptable
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Laboratories in Rochester, MN.

Performed

Monday – Friday.
Results available in 3-5 days.

Reference Range

By report.

Test Methodology

High-Pressure Liquid Chromatography (HPLC) with Fluorometric Detection.

Interpretation

Includes quantitation of coproporphyrins, uroporphyrins, and intermediate porphyrins (heptacarboxyl, hexacarboxyl, and pentacarboxyl).

CPT Codes

84120, 84110.

Contacts

Last Updated

10/12/2023