Diagnosis; Monitoring

Establish or confirm diagnosis

An equivalent option to urine for first-line test for evaluation of a suspected acute porphyria. Monitoring patients undergoing treatment for an acute intermittent porphyria or other acute porphyria.

Is research allowed on the sample after clinical testing is complete? Help
N/A

In a microcentrifuge tube, internal standard and plasma are combined, centrifuged, and then subjected to solid phase extraction (SPE). The SPE eluate is evaporated and the residue is then reconstituted and subjected to liquid chromatography tandem mass spectrometry analysis.(Unpublished Mayo method)

Tests performed
Entire test performed in-house

Accuracy was assessed by method comparison and the analysis of proficiency testing specimens and was acceptable. Intra assay precision was performed at 3 levels: CV results ranged from 7% to 17% for ALA and 4% to 6% for PBG (N=20 each). Inter assay precision was performed at 3 levels: CV … Accuracy was assessed by method comparison and the analysis of proficiency testing specimens and was acceptable. Intra assay precision was performed at 3 levels: CV results ranged from 7% to 17% for ALA and 4% to 6% for PBG (N=20 each). Inter assay precision was performed at 3 levels: CV results ranged from 15% to 19% for ALA and 5% to 9% for PBG (N=20 each). The analytical measurement range is 0.2 – 5.0 µmol/L for ALA and 0.1 – 10.0 µmol/L for PBG. View more

Additional testing must be performed to distinguish among the acute porphyrias. The specimen should be collected prior to treatment as therapy may decrease the amount of porphobilinogen (PBG) and aminolevulinic acid. Specimens should be protected from light and frozen immediately following collection. PBG is susceptible to degradation at high temperatures … Additional testing must be performed to distinguish among the acute porphyrias. The specimen should be collected prior to treatment as therapy may decrease the amount of porphobilinogen (PBG) and aminolevulinic acid. Specimens should be protected from light and frozen immediately following collection. PBG is susceptible to degradation at high temperatures and on prolonged exposure to light. View more

Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Formal PT program

PT Provider: Help
IPNET

Description of PT method: Help
Formal PT program.

Description of internal test validation method: Help
This test was laboratory developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements.

Software used to interpret novel variations Help
N/A

Laboratory's policy on reporting novel variations Help
N/A