Definition Alternative
Names How
the test is performed How
the test will feel What
the risks are
Why
the test is performed Normal
values
Note: mcg/dl = micrograms per deciliter Cost Special
Considerations What
abnormal results mean
Increased protoporphyrin levels may indicate:
Increased uroporphyrin levels may indicate:
How to
prepare for the test |
Definition Alternative
Names How
the test is performed
Infant: How
the test will feel What
the risks are Why
the test is performed Normal
values
Cost Special
Considerations What
abnormal results mean
How to
prepare for the test |
Porphyrins; urine |
Definition
A test that measures the level of
porphyrins in urine.
Alternative
Names
uroporphyrin
How the test
is performed
A 24-hour urine sample is needed.
The health care provider will instruct you, if necessary, to
discontinue drugs that may interfere with the test.
Infant:
Thoroughly wash the area around the urethra. Open a urine
collection bag (a plastic bag with an adhesive paper on one end),
and place it on your infant. For males, the entire penis
can be placed in the bag and the adhesive attached to the skin.
For females, the bag is placed over the labia. Place a diaper
over the infant (bag and all). The infant should be checked
frequently and the bag changed after the infant has urinated into
the bag. For active infants, this procedure may take a couple of
attempts--lively infants can displace the bag, causing an
inability to obtain the specimen. The urine is drained into the
container for transport to the laboratory.
Deliver it to the laboratory or your health care provider as soon
as possible upon completion.
How the test
will feel
Normal urination
What the risks
are
There are no risks.
Why the test
is performed
This test is most often performed
when porphyria or other disorder that can cause abnormal urine
porphyrins is suspected.
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,
but with 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
Note: mg = milligrams
Cost
The estimated cost is $15 to $30.
Special
Considerations
Drugs that can affect test
measurements include aminosalicylic acid, barbiturates, chloral hydrate, chlorpropamide, ethyl alcohol, griseofulvin, morphine, oral contraceptives, phenazopyridine, procaine, and
sulfonamides.
What abnormal
results mean
Increased levels of urinary PBG
may indicate
How to prepare
for the test
The health care provider may advise
you to discontinue drugs that can affect the test (see Special
considerations).
If the collection is being taken from an infant, a couple of
extra collection bags may be necessary.
Images
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Definition Alternative
Names How
the test is performed
Infant: How
the test will feel What
the risks are Why
the test is performed Normal
values Cost Special
Considerations What
abnormal results mean
Decreased levels may occur with chronic liver disease. How to
prepare for the test |
Definition Alternative
Names How
the test is performed How
the test will feel What
the risks are Why
the test is performed Normal
values Cost Special
Considerations What
abnormal results mean
How to
prepare for the test |