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Porphyrins, blood 
 

Definition
This test measures total red blood cell porphyrins.

Porphyrins are pigments found in both animal and plant life. 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 porphyrins.

Alternative Names
uroporphyrin levels; protoporphyrin levels; porphyrins, total; coproporphyrin levels

How the test is performed
Blood is drawn from a vein (venipuncture), usually 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. This 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. During the procedure, the tourniquet is removed to restore circulation. 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.

How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

What the risks are
Risks associated with venipuncture are slight:

  • excessive bleeding
  • fainting or feeling lightheaded
  • hematoma (blood accumulating under the skin)
  • infection (a slight risk any time the skin is broken)
  • multiple punctures to locate veins

Why the test is performed
This test is used to diagnose porphyrin disorders involving red blood cells.

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

  • 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

Cost
Information not available.

Special Considerations
Failure to comply with dietary restrictions prior to the test may alter and invalidate test results.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

What abnormal results mean
Increased levels of coproporphyrins may indicate:

Increased protoporphyrin levels may indicate:

Increased uroporphyrin levels may indicate:

How to prepare for the test
Fasting for 12 to 14 hours prior to this test is required. You may drink water right before the test.

If your child is to have this test performed it may be helpful to explain how the test will feel, and even practice or demonstrate on a doll. The more familiar your child is with what will happen to them, and the purpose for the procedure, the less
anxiety they will feel.



PBG 
 

Definition
A test that measures the amount of PBG in urine.

Alternative Names
PHB; porphobilinogen

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.

  • 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.
  • Cap the container. Keep it in the refrigerator or a cool place during the collection period. Label the container with your name, the date, the time of completion, and return it as instructed.

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
This test involves only normal urination, and there is no discomfort.

What the risks are
There are no risks.

Why the test is performed
This test may be performed when porphyria or another disorder associated with abnormal PBG level is suspected.

PBG is a substance (
enzyme) used by the body to synthesize porphyrins (nitrogen containing organisms). 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

  • random urine: negative test
  • 24-hour urine: 1.5 to 2 mg (milligrams) per 24-hours

Cost
The estimated cost is $12 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
No special preparation is necessary for this test, but if the collection is being taken from an infant, a couple of extra collection bags may be necessary.




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.


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Delta-ALA 
 

Definition
A test that measures the amount of delta-ALA in urine.

Alternative Names
delta-aminolevulinic acid

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.

  • 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.
  • Cap the container. Keep it in the refrigerator or a cool place during the collection period. Label the container with your name, the date, the time of completion, and return it as instructed.

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.

Avoid exposure of the urine to direct light.

How the test will feel
The test involves only normal urination and there is no discomfort.

What the risks are
There are no risks.

Why the test is performed
This test is useful in detecting specific liver abnormalities.

Delta-ALA is a chemical produced from
amino acids in the liver. It is the basic "building block" for the synthesis of porphyrins. The most important function of porphyrins are as components of heme (which is the major building block of hemoglobin). Oxygen binds to the iron in the heme molecules.

Various kinds of porphyrins exist with the same basic structure but with slightly different chemical "side-chains". The major biochemical pathway is delta-ALA -->
PBG --> uroporphyrin --> coproporphyrin --> protoporphyrin --> heme. Each step in the pathway requires a specific enzyme. If any of the enzymes is deficient, a type of porphyria results.

Normal values
1 to 7 mg per 24-hours

Note: mg = milligrams

Cost
The estimated cost is $98.

Special Considerations
Interfering factors:
Drugs that may increase test measurements include penicillin,
barbiturates, oral contraceptives, and griseofulvin.

What abnormal results mean
Increased levels of urinary delta-ALA may indicate:

  • lead poisoning
  • porphyria (several types)

Decreased levels may occur with chronic liver disease.

How to prepare for the test
No special preparation is necessary for this test, but if the collection is being taken from an infant, a couple of extra collection bags may be necessary.



Wood's lamp 
 

Definition
A test performed in a dark room where ultraviolet light is shined on the area of interest to detect the presence of infectious organisms which contain substances that glow on the skin in the presence of ultraviolet light.

Alternative Names
black light test; ultraviolet light test

How the test is performed
You will be seated, and the lights will be turned off. After your eyes adjust to the darkness, the Wood's lamp is turned on and held 4 to 5 inches from the area being studied. Take care not to look directly into the light.

How the test will feel
The test involves sitting while your health care provider shines the ultraviolet light over the skin being studied.

What the risks are
There are no risks, but avoid looking directly into the ultraviolet light, as you avoid looking into the sun.

Why the test is performed
Your health care provider may perform this test to detect several conditions, including:

Normal values
Normally your skin will not fluoresce, or shine under the ultraviolet light.

Cost
Information not available.

Special Considerations
Washing before the test may cause a false negative result. A room that is not dark enough may also alter results. Other materials may alter results. For example, deodorants, make-up, tetracycline and soaps in the sweat may fluoresce. Some species of tinea capitis lack porphyrins and therefore will not fluoresce

What abnormal results mean
Under the ultraviolet light, different infections and conditions show different colors:

  • golden yellow (Tinea versicolor)
  • pale green (trichophyton schoenleini)
  • bright yellowgreen (Microsporum audouini or M. canis)
  • aquagreen to blue (Pseudomonas aeruginosa)
  • pink to pinkorange (Porphyria cutanea tarda)
  • ash-leaf-shaped spot (Tuberous sclerosis)
  • bluewhite (Leprosy)
  • pale white (hypopigmentation)
  • purplebrown (hyperpigmentation)
  • cold, bright white, or bluewhite (depigmentation, vitiligo)
  • cold, bright white (albinism)
  • coralred, pink (erythrasma)

How to prepare for the test
It is important not to bathe or shampoo for 24-hours before your test, because porphyrins (a substance found in the suspect organisms) are removed with soap and water.


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