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Porphobilinogen (PBG) Deaminase, Erythrocyte Test

        This test is significant in evaluating  most AIP patients.  However
there are 14% of AIP patients who will not have a decrease in the PBG-D.

        The test is performed through enzymatic study and fluorometry.
Porphobilinogen (PBG) deaminase (also called uroporphyrinogen-1-synthase and hydroxymethylbilane synthase) is present in red cells and catalyzes the formation of uroporphyrinogen from porphobilinogen.

         In persons genetically susceptible acute intermittent porphyria (AIP), PBG deaminase levels are approximately half of usual values, except in the 14% aforementioned.

       . Normal levels of erythrocyte PBG deaminase, however, do not exclude rare abnormal forms of hepatic PBG deaminase measured activity.

        Measurement of porphobilinogen deaminase activity is of
limited use in assessing patients with latent acute intermittent porphyria.
It is best for only those patients who are acute or chronic.

        The clinical usefulness of PBG deaminase is limited both technically
and clinically.

        Test reference levels: Adult: 2.10-4.30 mU/g HGB.

Dr. Robert Johnson MD

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  Porphyrin Red Blood Cell Testing

        Another of the tests for porphyria is that of the porphyrin red
blood cell.

        Often it is given in conjunction with a 24 porphyrin urine test.
Other names for this tests are: uroporphyrin levels; protoporphyrin
levels; porphyrins, total; coproporphyrin levels

        Porphyrins are pigments found in both animal and plant life.
The Nobel Laureate, Hans Fischer in 1930,  called porphyrins that which
"make the grass green, and the blood red".

        Coproporphyrin, protoporphyrin, and uroporphyrin are three
porphyrins related to red blood cells that can normally be measured in small amount in the human blood stream.

        Protoporphyrin is normally found in highest quantity and thus this
test is occasionally known as the PROTO test.

        Additional tests must be performed to know the levels of specific

        The test is undertaken by drawing blood  from a vein (venipuncture).

        The point of entry is often  from the inside of the elbow or the
back of the hand.

        The puncture site is cleaned with antiseptic, and a tourniquet (an
elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein.

        When this is done it  causes veins below the tourniquet to distend
(fill with blood).

        A needle is inserted into the vein, and the blood is collected in
an air-tight vial or a syringe.

        Midway through the  procedure, the tourniquet is removed so that
the blood  circulation cam resume.  Once the blood has been collected, the
needle is removed, and the puncture site is covered to stop any bleeding.

    The sample is then placed in ice and taken immediately to the laboratory.

       Sometimes when the needle is inserted to draw blood, it is found that
some people will feel moderate pain. The majority of people will  feel only
a prick or stinging sensation. Afterward, there may be some throbbing.

        The test is performed do that physicians can diagnose porphyrin
disorders involving red blood cells.

        This test specifically measures total porphyrin levels, but
reference values for the individual components are also included:

The normal value ranges are as follows:
total porphyrin levels: 16 to 60 mcg/dl
coproporphyrin levels: < 2 mcg/dl
protoporphyrin levels: 16 to 60 mcg/dl
uroporphyrin levels: < 2 mcg/dl
Note: mcg/dl = micrograms per deciliter

            It must be remembered that when you undertake this test you must
follow the dietary restrictions. If you do not follow the dietary
restrictions it will often  alter and invalidate test results.

            When you test results show abnormal increased levels of
coproporphyrins, it may indicate  congenital erythropoietic porphyria,
as well as sideroblastic anemia.

        Increased protoporphyrin levels may indicate that the patients has
infection, thalassemia, sideroblastic anemia, lead poisoning,
iron deficiency anemia, erythropoietic anemia , or increased erythropoiesis.

        Increased uroporphyrin levels often indicate erythropoietic
protoporphyria. [EOO]. This test must be ordered by your physician.

        In order to prepare for the test you must be fasting for 12 to 14
hours prior to the time of  this test. You may drink water right before
the test.

        If you have any carbohydrate intake, you will compromise your test.
Therefore you must avoid the carbohydrates during the time
preceeding the blood draw.

Dr. Robert Johnson MD

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 Fecal Matter Testing

Fecal Porphyrin Test The patient must collect the stools over a three day period after carefully following dietary and pharmaceutical restrictions. The patients must have been off of most drugs for a minimum of four days and have avoided certain foods for 4 to 7 days.

The test is completed by the use of high performance liquid chromatography known as (HPLC).

The significance of the fecal porphyrin tests is that fecal porphyrins are elevated in disorders such as variegate porphyria [VP], hereditary coproporphyria [HCP] and erythropoietic protoporphyria [EPP] .

Coproporphyrins can also be elevated in a variety of acquired conditions, such as liver disease and by diet.

The stool porphyrins will be normal in acute intermittent porphyria. Reference Interval:

Coproporphyrin: 0-45 nmol/g dry weight
Protoporphyrin: 0-150 nmol/g dry weight

Please realize that bacterial modifications of fecal porphyrins are extensive.
Dr. Robert Johnson MD

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