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TESTING FOR PORPHYRIA



24 HOUR PORPHYRIN URINE TEST

        The Porphyrin Urine Tests is a  test that measures the level of
porphyrins in urine.

        An alternative name for this test is The Uropoprhyrin Test.

        The test is performed by the collection of a urine for a 24-hour
period.

        The test must be ordered by a physician. The ordering physician
will  instruct you, if necessary, to discontinue drugs that may interfere with the test.

        Be sure that the proper preservative has been added to the
collection jug before leaving your doctor's office. Many a porphyrin urine
test has been compromised because of the wrong perservative being used or lack of a preservative.

        On day 1, urinate into the toilet upon arising in the morning.

        Collect all subsequent urine (in a special container) for the next
24-hours.

        On day 2, urinate into the container in the morning upon arising.

        Always cap the container.

        Always void into a special "hat" which fits into the average toilet seat.

        Do not let the voided urine sit in the hat.  Pour it immediately
into the collection jug. Exposure to air will compromise the collection.

        Try to void with no direct light  as exposure of urine to light will
diminish the number of porphyrin, and the higher number of porphyrin
in the urine,  is what is needed for an accurate test assay.

        Be sure that no toilet tissue touches the collection as chemicals
in paper products will compromise the collection.

        Keep it in the refrigerator or a cool place during the collection
period.  Ideally the temperature should run between 36-40 degrees, that of
the standard refrigerator setting.

        Always be sure that the container is marked with your name, the
date, the time of completion, and return it as instructed. Do not let it sit
out in room temperatures or in bright light.

    Be sure the receptionist at the lab takes it to the proper storage
in the lab immediately. Ascertain that it has been properly stored
at the lab.  Find out when it will be transported and how it will be
transported to the assaying laboratory. ALso find out when the assay is to
be run and when the results will be know.  Asking these questions helps
alleviate any problems of a lost specimen and/or compromised tests results. There are no risks in performing this test.

    The reason that this test is performed  is because of a high degree of
suspicion that the patient may have porphyria.

        The most important function of porphyrins is as components of heme.
Heme is made from iron + protoporphyrin.

        Hemoglobin is made up of four globin proteins + 4 heme groups.
Oxygen binds to the iron in the heme molecules.

        Various kinds of porphyrins exist with the same basic structure.
 However the various kinds of porphyrins  have slightly different chemical
appearance.

        The major biochemical pathway includes conversions from
porphyrins to delta-ALA, then to PBG, then uroporphyrin,
then coproporphyrin, then protoporphyrin, and finally into the end product, heme.

        Each step requires the presence of an enzyme. If any of the enzymes
are deficient (because of a genetic disease or inhibition by a toxic
substance), a type of porphyria results. Normal values for porphyria
urine tests are as follows: random urine: negative test
24-hour urine: 50 to 300 mg per 24-hours Note: mg = milligrams

        Before you undertake this porphyrin urine test you must determine
whether you have taken any drugs which can affect test measurements.

        These drugs include aminosalicylic acid, barbiturates, chloral
hydrate, chlorpropamide, ethyl alcohol, griseofulvin, morphine, oral
contraceptives, phenazopyridine, procaine, and sulfonamides.

        Abnormal tests results which result in increased levels of urinary
PBG may indicate porphyria (several types), hepatic carcinoma (liver
cancer), hepatitis  or lead poisoning .

        All too often porphyrin tests must be repeated a number of times.
Timing is important for many of the tests. The best time to test is
at the onset of an acute attack and BEFORE   GLUCOSE infusion has begun.

Dr. Robert Johnson, MD

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