Porphyria Test in Ahmedabad : Total Porphyrins, δ-amino levulinic acid (δ-ALA) and Porphobilinogen
Urinary total Porphyrins, δ-amino levulinic acid (δ-ALA) and Porphobilinogen are 3 most commonly done tests for the diagnosis and management of various types of porphyrias.
A doctor will prescribe/order these tests when you have symptoms related to cutaneous porphyria or neurologic porphyria. Symptoms include but not limited to, blisters or redness or scars on sun exposed skin parts, muscle weakness, tingling and/or numbness in legs or hands, abdominal pain, mood/though alternations.
Neurologic porphyrias are associated with acute attacks involving the nervous system and/or gastrointestinal tract. They include acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), and ALA dehydratase deficiency porphyria (ADP).
Cutaneous porphyrias produce skin-related symptoms. This type includes porphyria cutanea tarda, (PCT), erythropoietic protoporphyria (EPP) and congenital erythropoietic porphyria (CEP).
Tests for porphyria may include measurement of porphrins or their precursors in urine
- Porphobilinogen (PBG), a porphyrin precursor, in spot urine or 24 hours urine. Porphobilinogen (PBG) is a porphyrin precursor excreted in urine in patients with Acute intermittent porphyria
(AIP), Porphyria variegate (PV) and Hereditary coproporphyria. Acute attacks of porphyria in individuals with the trait can be caused by drugs like Barbiturates, Sulphonamides, Aminophylline, Griseofulvin and Oral contraceptive agents which increase the synthesis of 5-ALA and PBG. In general, PBG is the more important of the precursors whereas ALA measurement is used as a supplemental test. Test cost price Rs 3500 , sample 24 hours urine or Random(spot) urine.
- Delta-aminolevulinic acid (ALA) or 5-AMINOLEVULINIC ACID (5 -ALA), another porphyrin precursor, in spot urine or 24 hours urine. Delta Amino levulinic Acid shows a marked increase in cases of Porphyrias during an acute attack. The levels fall to normal after the acute episode except in cases of Acute intermittent porphyria and Hereditary coproporphyria. Test cost price Rs 4000 , sample 24 hours urine or Random (spot) urine.
- Porphyrins, Total : in 24 hrs / random/spot urine . This assay demonstrates increased levels of Total Porphyrins in the urine in cases of Congenital erythropoietic porphyria, Porphyria cutanea tarda & Mixed porphyria. All patients presenting with photosensitive dermatosis should be tested for Porphyrins. To differentiate Porphyrias and Lead intoxication, the determination of Porphyrins is usually combined with Urinary 5-ALA and Porphobilinogen (PBG). Drugs that may precipitate Porphyria are Antipyretics, Barbiturates, Phenylhydrazine and Sulphonamides. Test cost price Rs 4400 , sample 24 hours urine or Random(spot) urine.
- Porphyrins Speciation, 24Hrs Urine : The Porphyrins Speciation Profile measures seven porphyrins namely : Uroporphyrin I, Heptacarboxyporphyrin I, Hexacarboxyporphyrin I, Pentacarboxyporphyrin I, Coproporphyrin I, Coproporphyrin III, and total porphyrins and is helpful to differentiate heavy metal toxicity, as well as for monitoring patients on therapy.
For example, a decreased level of porphobilinogen deaminase confirms the diagnosis of acute intermittent porphyria.
|TYPE OF PORPHYRIA||URINE ALA AND PBG*||URINE PORPHYRINS||FECAL PORPHYRINS||RED BLOOD CELL PORPHYRINS|
|Acute intermittent porphyria||Increased||Increased URO*||Normal||Normal|
|Variegate porphyria||Increased||Increased COPRO||Increased PROTO, COPRO||Normal|
|Hereditary coproporphyria||Increased||Increased COPRO||Increased COPRO||Normal|
|ALA dehydratase deficiency||Increased ALA only||Increased COPRO||Increased PROTO|
|Porphyria cutanea tarda||Normal||Increased URO, 7-carboxyl||Increased Isocoproporphyrin||Normal|
|Erythropoietic Protoporphyria||Normal||Normal||Increased PROTO||Increased PROTO|
|Congenital erythropoietic porphyria||Normal||Increased URO, COPRO||Increased COPRO||Increased URO, COPRO|
|PBG = Porphobilinogen; ALA = Aminolevulinic acid; URO = Uroporphyrin; COPRO = Coproporphyrin; PROTO = Protoporphyrin|
Table adapted from: “Iron and porphyrin metabolism,” Clinical Chemistry: Theory, Analysis and Correlation, courtesy of William E. Schreiber, MD. Table for enzyme deficiency
Sample collection precautions : Please contact lab for special precautions which needs to be taken for sample collection. Use dark colored container or wrap completely with black paper or aluminium foil. Porphyrins are susceptible to degradation at high temperature, at pH <7.0, and on exposure to light.
Test results or report comes in around 4-5 days for the above tests. Test results should be interpreted cautiously as normal results can be there in between attacks and increased/decreased levels can be there with other conditions. Results to be interpreted in context keeping clinical and other tests in mind.
Confirmatory tests are enzyme tests which are deficient (8 enzymes in the pathway) or genetic testing : both of which are not widely available or can be outsourced to USA. For example, a decreased level of porphobilinogen deaminase confirms the diagnosis of acute intermittent porphyria. Fecal and red blood cell porphyrins tests are also not widely available.