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HelpTest Code LAB123 Porphyrins Evaluation, Whole Blood
Reporting Name
Porphyrins Evaluation, WBSCH Clinical System Name: Porphyrin, Total
Useful For
Establishing a biochemical diagnosis of erythropoietic protoporphyria and X-linked dominant protoporphyria
Ordering Guidance
This is the preferred test for assessment for protoporphyria. The preferred test for assessing lead toxicity in children is blood lead. For more information see PBDV / Lead, Venous, with Demographics, Blood or PBDC / Lead, Capillary, with Demographics, Blood. The preferred screening test for suspicion of a hepatic porphyria is urine porphyrins. For more information see PQNRU / Porphyrins, Quantitative, Random, Urine.
Necessary Information
Include a list of medications the patient is currently taking.
Specimen Required
All porphyrin tests on whole blood can be performed on 1 collection tube.
Patient Preparation: Patient must not consume any alcohol for 24 hours before specimen collection.
Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Dark blue top (metal free heparin), green top (lithium heparin), lavender top (EDTA)
Specimen Volume: 4 mL
Collection Instructions: Immediately place specimen on wet ice.
Specimen Type
Whole bloodSpecimen Minimum Volume
3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole blood | Refrigerated | 7 days |
Day(s) Performed
Monday through Friday
TAT: 5 - 6 days
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Method Name
Spectrofluorometric
Method Description
This evaluation is performed as a 2-step analysis. First, the total red blood cell (RBC) porphyrin concentration is determined by extracting the porphyrins from washed, resuspended RBCs using a mixture of ethyl acetate and acetic acid. The porphyrins are then back extracted into dilute hydrochloric acid. Total porphyrins are quantified using this extract via spectrofluorometry.(Piomelli S. Free erythrocyte porphyrins in the detection of undue absorption of Pb and Fe deficiency. Clin Chem. 1977;23:264-269; Gou EE, Balwani M, Bissell DM, et al. Pitfalls in erythrocyte protoporphyrin measurement for diagnosis and monitoring of protoporphyrias. Clin Chem. 2015;61[12]:1453-1456. doi:10.1373/clinchem.2015.245456)
If the total porphyrin concentration is elevated, the RBCs are re-extracted to separate and quantify the zinc-complexed and noncomplexed (free) protoporphyrin via high-performance liquid chromatography.(Smith RM, Doran D, Mazur M, Bush B. High-performance liquid chromatographic determination of protoporphyrin and zinc protoporphyrin in blood. J Chromatogr. 1980;181[3-4]:319-327; Gou EE, Balwani M, Bissell DM, et al. Pitfalls in erythrocyte protoporphyrin measurement for diagnosis and monitoring of protoporphyrias. Clin Chem. 2015;61[12]:1453-1456. doi:10.1373/clinchem.2015.245456)
Reference Values
PORPHYRINS, TOTAL, RBC
<80 mcg/dL
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84311
82542-if appropriate
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PEE | Porphyrins Evaluation, WB | 2814-2 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 88886 | Total Porphyrins, WB | 2814-2 |
| 29356 | Interpretation | 59462-2 |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| PPFE | Protoporphyrins, Fractionation, WB | Yes | No |
Testing Algorithm
This test is recommended for screening patients for possible erythropoietic protoporphyria and X-linked dominant protoporphyria. In addition, it can be used for evaluation of iron-deficiency anemia and chronic lead intoxication. Testing begins with total erythrocyte porphyrins. If the result is below 80 mcg/dL, it is normal, and testing is complete.
If the total erythrocyte porphyrin value is 80 mcg/dL or above, the protoporphyrin fractionation assay will automatically be performed at an additional charge. The fractionation test results include noncomplexed (free) protoporphyrin and zinc-complexed protoporphyrin.
The following algorithms are available:
Special Instructions
Report Available
3 to 5 daysReject Due To
| Gross hemolysis | Reject |
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.