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HelpTest ID PEWE Porphyrins Evaluation, Washed Erythrocytes
Useful For
Preferred test for analysis of erythrocyte porphyrins
Establishing a biochemical diagnosis of erythropoietic protoporphyria and X-linked protoporphyria
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| PPFWE | Protoporphyrins, Fractionation, RBC | Yes | No |
Testing Algorithm
This test is recommended for screening patients for possible erythropoietic protoporphyria and X-linked 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:
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Washed RBCOrdering 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.
For suspected hepatic porphyria, the preferred screening test is urine porphyrins. For more information, see PQNRU / Porphyrins, Quantitative, Random, Urine.
Necessary Information
1. Volume of packed cells and total volume of specimen (red cells + saline) are required and must be sent with specimen.
2. Include a list of medications the patient is currently taking.
Specimen Required
Patient Preparation: For 24 hours before specimen collection, patient must not consume any alcohol.
Collection Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Dark blue top (metal free heparin), green top (lithium heparin), or lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: Entire washed erythrocyte suspension
Collection Instructions:
Collect and process whole blood specimen as follows:
1. Transfer entire specimen to a 12-mL graduated centrifuge tube.
2. Centrifuge specimen at 4° C for 10 minutes at 2000 rpm.
3. Record volume of packed cells and the total volume of the specimen.
4. Discard supernatant plasma.
5. Wash packed erythrocytes 2 times by resuspension of at least an equal amount of cold 0.9% saline, mix, and centrifuge for 5 minutes at 2000 rpm, discarding supernatant after each washing.
6. Resuspend packed cells to the original total volume with 0.9% saline. Invert specimen gently to mix.
7. Transfer washed erythrocytes into a plastic vial and freeze.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Washed RBC | Frozen (preferred) | 14 days |
| Refrigerated | 14 days |
Special Instructions
Reference Values
<80 mcg/dL
Day(s) Performed
Monday through Friday
CPT Code Information
84311-Spectrophotometry, analyte not elsewhere specified
82542-Chromatography (if appropriate)
Report Available
3 to 5 daysReject Due To
| Cell suspension not available | Reject |
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.