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Test Code PPFWE Protoporphyrins, Fractionation, Washed Erythrocytes

Reporting Name

Protoporphyrins, Fractionation, RBC

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Preferred test for analysis of erythrocyte protoporphyrin fractions

 

Preferred test for evaluating patients with possible diagnoses of erythropoietic protoporphyria and X-linked dominant protoporphyria

 

Establishing a biochemical diagnosis of erythropoietic protoporphyria, or X-linked dominant protoporphyria

Method Name

High-Performance Liquid Chromatography (HPLC) with Fluorescence Detection


Ordering Guidance


This test is for assessment for protoporphyria, an erythropoietic porphyria. The preferred test for 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


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


All porphyrin tests on erythrocytes can be performed on 1 tube.

 

Patient Preparation: Patient must not consume any alcohol for 24 hours before specimen collection.

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 Type

Washed RBC

Specimen Minimum Volume

1 mL of washed and resuspended erythrocytes

Specimen Stability Information

Specimen Type Temperature Time Special Container
Washed RBC Frozen (preferred) 14 days
  Refrigerated  14 days

Reject Due To

Cell suspension not available Reject

Reference Values

FREE PROTOPORPHYRIN

<20 mcg/dL

 

ZINC-COMPLEXED PROTOPORPHYRIN

<60 mcg/dL

Interpretation

Abnormal results are reported with a detailed interpretation that may include an overview of the results and their significance, a correlation to available clinical information provided with the specimen, differential diagnosis, and recommendations for additional testing when indicated and available.

Day(s) Performed

Monday through Friday

Report Available

3 to 5 days

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

82542

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PPFWE Protoporphyrins, Fractionation, RBC 94490-0

 

Result ID Test Result Name Result LOINC Value
31932 Zinc-Complexed Protoporphyrin 2895-1
31933 Free Protoporphyrin 94491-8
INTP6 Interpretation 59462-2
BG571 Total cell suspension 94496-7
BG572 Packed cell volume 94497-5

Testing Algorithm

This test should not be ordered in conjunction with PEWE / Porphyrins Evaluation, Washed Erythrocytes.

 

The following algorithms are available:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm

-The Heme Biosynthetic Pathway