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Test ID: PEWE    
Porphyrins Evaluation, Washed Erythrocytes

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Method Description Describes how the test is performed and provides a method-specific reference

This evaluation is performed as a 3-step analysis. First, the total 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)


If the total porphyrin concentration is elevated, the RBCs are re-extracted using an acetone:water solution. This extraction allows for separation and quantification of zinc-complexed and noncomplexed (free) protoporphyrin via HPLC.(Ford RE, Ellefson RD: Quantitation of erythrocyte protoporphyrins and zinc protoporphyrin by high-pressure liquid chromatography. Clin Chem 1984;30:972)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.

Monday through Friday; 8 a.m.

Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.

3 days (not reported on Saturday or Sunday)

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result

4 days

Performing Laboratory Location The location of the laboratory that performs the test