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PORPHOBILINOGEN, urine (087-0159)
Test Mnemonic:

PBG-U

Specimen Requirements:

25 mL random urine (preferred) or 25 mL aliquot of a 24-hour urine collection.  Protect from light and refrigerate (for up to 24 hours) or freeze (for longer than 24 hours).

Test Included:

Urine delta-aminolevulinic acid & total porphyrins.

Collection:

Random urine sample with no preservative is preferred.  It should be light protected, refrigerated (if stored up to 24 hours) or frozen (if stored for longer than 24 hours).  A 24 hour urine collection is an alternative. For collecting a 24 hour urine, obtain a suitable container (dark brown or wrapped in foil for light protection), add 5 grams of sodium carbonate to the container before starting the collection.  The container must be refrigerated during and after the collection period. For timing the 24 hour collection: a) choose and record a start/opening time (e.g. 8 AM - the closing time will then be 8 AM the next day), b) open the urine collection at the start/opening time by emptying the bladder and discarding that urine so the bladder is empty at the start of the collection, c) add all urine to the container for the next 24 hours, d) close the collection after exactly 24 hours by voiding and adding that urine to the collection for the last time.  After the collection is complete, mix it well, remove an aliquot of at least 25 mL to a light protected container and refrigerate (for up to 24 hours) or freeze at -20 degrees C (if stored for longer than 24 hours). 

Container:

Urine cup with screw cap protected from light (foil-wrapped) or 24-hour brown or foil-wrapped urine bottle.

Minimum Volume:

25 mL random urine sample (preferred) or 25 mL aliquot of a 24-hour collection.

Storage/Transport:

Use dark or aluminum foil-wrapped container to protect from light.  Refrigerate during collection of a 24-hour urine.  Refrigerate (for up to 24 hours) or freeze random urine or 24-hour urine aliquot (for storage longer than 24 hours).  See Shipping Instructions for more details.

Specimen Preparation:

25 mL of random urine specimen or 25 mL aliquot of a 24-hour sample with recorded information that includes the total volume of the 24 hour urine. 

Stability:

Stable when light protected and refrigerated for up to at least 24 hours or frozen for up to 2 months.

Causes for Rejection:

Samples not protected from light, not refrigerated or not frozen, will not be rejected, but their condition on arrival will be recorded in the results report. 

Reference Range:

0 - 4 mg/24 hours.  Sample are expressed per L and per gram creatinine to aid in interpreting the results. 

Turnaround Time:

Routine; test is performed weekly.  If a result is needed urgently for clinical diagnosis the lab should be notified by phone (409-772-9103), and it can usually be provided by phone, fax or email one business day after arrival of the sample in the lab. 

Methodology:

Ion exchange column chromatography

Performed:

Samples are received 24 hours per day at Sample Management, 7.412 CSW or from 8 AM - 5 PM, Monday - Friday at Room 3.102 Ewing Hall, 700 Harborside Drive, Galveston, TX 77555-1109; Phone: (409) 772-9103 or 4661.  Outside samples are delivered to the laboratory by overnight carriers or through internal delivery. 

Lab:

Porphyria Laboratory

Clinical Indication:

Screening for acute porphyrias, e.g. acute intermittent porphyria (AIP).

Patient Preparation :

Not applicable.

CPT 4 Code:

84110

Note:

Call the Porphyria Laboratory at 409-772-9103 or 409-772-4661 if there are questions.

When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient. Components of the organ or disease panels may be ordered individually. The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-10 code or its verbal equivalent.
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