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PORPHOBILINOGEN DEAMINASE, erythrocytes (087-0252)
Test Mnemonic:


Specimen Requirements:

7 mL of whole blood; protect from light and refrigerate.  Mix well but gently before processing.  Determine and record the hematocrit value.  Aliquot the sample to small plastic tubes and seal tightly for storage.  These are immediately placed in the freezer in the horizontal position to prevent separation of cells and plasma by gravity, or flash frozen using acetone-dry ice or liquid nitrogen. 


Routine venipuncture.


Green-top tube (heparin).

Minimum Volume:

0.5 mL


Protect from light and refrigerate.  See Shipping Instructions for more details.

Specimen Preparation:

Whole blood


Stable when light protected and refrigerated or frozen.

Causes for Rejection:

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

Reference Range:

20  - 50 nmol/mL erythrocytes/hr

Turnaround Time:

Routine; test is performed semi-weekly.


Enzyme assay using porphobilinogen (PBG) as substrate and measuring uroporphyrin as a derivative of the product. 


Samples are accepted 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.


Porphyria Laboratory


Hydroxymethylbilane synthase (HMBS).

Clinical Indication:

A second line test for acute porphyrias, to help differentiate acute intermittent porphyria (AIP) from the other acute hepatic porphyrias.

Patient Preparation :

Not applicable

CPT 4 Code:



Call Porphyria Laboratory (409-772-9103 or 4661) with any 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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