Diagnosis

Establish or confirm diagnosis

Diagnosis of congenital erythropoietic porphyria. This test is not useful for diagnosis of acute intermittent porphyria (AIP).

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

Washed cells are incubated with aminolevulinic acid as substrate and the series I and III porphyrin isomers formed are measured. The proportion of series III isomers formed in relation to total porphyrins (I + III isomers) represents the uroporphyrinogen III synthase activity. The values are reported as Relative Units.(Unpublished Mayo … Washed cells are incubated with aminolevulinic acid as substrate and the series I and III porphyrin isomers formed are measured. The proportion of series III isomers formed in relation to total porphyrins (I + III isomers) represents the uroporphyrinogen III synthase activity. The values are reported as Relative Units.(Unpublished Mayo method) View more

Tests performed
Entire test performed in-house

Accuracy was assessed by analysis of normal and abnormal specimens; all samples were clinically concordant. Intra assay precision was performed at 3 levels: CV results ranged from 0.6% to 2.3% (N=3 each). Inter assay precision was performed at 3 levels: CV results ranged from 1.1% to 4.7% (N=3 each). The … Accuracy was assessed by analysis of normal and abnormal specimens; all samples were clinically concordant. Intra assay precision was performed at 3 levels: CV results ranged from 0.6% to 2.3% (N=3 each). Inter assay precision was performed at 3 levels: CV results ranged from 1.1% to 4.7% (N=3 each). The analytical measurement range is 0-25.0 µg/dL. View more

This test is not useful for ruling out acute intermittent porphyria (AIP), a disorder caused by decreased uroporphyrinogen I synthase (also known as porphobilinogen deaminase). For AIP, order PBGD_ / Porphobilinogen Deaminase, Whole Blood. This test does not reliably distinguish between individuals who are carriers for congenital erythropoietic porphyria (CEP) … This test is not useful for ruling out acute intermittent porphyria (AIP), a disorder caused by decreased uroporphyrinogen I synthase (also known as porphobilinogen deaminase). For AIP, order PBGD_ / Porphobilinogen Deaminase, Whole Blood. This test does not reliably distinguish between individuals who are carriers for congenital erythropoietic porphyria (CEP) and are at risk for having an affected child. If possible, specimens from patients suspected of having CEP should be collected prior to blood transfusions; uroporphyrinogen (UPG) III synthase activity in transfused erythrocytes can cause false-negative results. Abstinence from alcohol for at least 24 hours is essential for accurate results. While the effects of alcohol on this enzyme have not yet been determined, alcohol is known to suppress or induce other enzymes in the heme biosynthetic pathway. View more

Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Intra-Laboratory

Description of PT method: Help
Intra-laboratory alternative assessment of performance through quality control or patient blind testing.

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