ALA (Aminolevulinic acid), porphobilinogen, and porphyrins urine test

Your doctor may ask you to get this test if you have symptoms of porphyria or if you have a family history of porphyria. 

Porphyrias can cause neurological symptoms or cutaneous (skin) symptoms.

The neurological symptoms include:

• Confusion
• Hallucinations
• Tingling sensation in the hands and feet
• Numbness of the hands and feet
• Abdominal pain and nausea
• Constipation 
• Urinary retention 

These symptoms occur together as acute attacks and may last for days or even weeks. All the symptoms could be triggered by factors such as changes in the diet, stress, a variety of medications and exposure to toxic substances. 

The skin symptoms of porphyria include:

• Blisters
• Scarring
• Hyperpigmentation 
• Swelling
• Itching 
• Burning sensation
• Redness

These symptoms will appear on the areas of the skin which are exposed to the sun. 

In individuals who have already been diagnosed with porphyria, the test may be done regularly to monitor the condition.

The porphobilinogen urine test is one of the primary tests for neurological porphyrias. If the readings are abnormal, it is followed by the urine porphyrins test, which checks for coproporphyrin and uroporphyrin. 

The ALA test is helpful in diagnosing ALA dehydratase deficiency porphyria, a rare disorder. ALA is also elevated in other neurological porphyrias and may be ordered along with porphobilinogen. 

A urine porphyrin test is the best diagnostic tool for erythropoietic protoporphyria, a cutaneous porphyria. The urine test for porphyrin is also abnormal in congenital erythropoietic porphyria, a rare condition in which children are extremely sensitive to light.

In case you have symptoms of neurologic porphyria, it is best to collect the sample during an acute attack.

If you are taking any medicines, such as antibiotics, birth control medications or medications for reducing anxiety, then you must inform the doctor before the test. You must refrain from the consumption of alcohol for at least 24 hours before undergoing the test. If you are pregnant, inform the doctor before the collection of the sample.

This test is typically conducted on a 24-hour urine sample. You will be provided with a container to collect the sample. It is best to start collecting the sample early in the morning. Here is how you can collect the sample:

• Do not collect the first urine of the day but mark it as the beginning of the 24 hour period. 
• For the next 24 hours, collect samples every time you urinate. 
• The container with the urine must be stored in a cool environment or can be kept in a refrigerator. Label the container appropriately with your name, the date and time of collection of the sample. 
• After the sample has been collected (in the time period of 24 hours), it must be taken to the laboratory for analysis. 

If the test is being performed on an infant, you will be provided with a urine collection bag along with the container. Make sure to clean the area around the urethral opening of the baby and place the bag on appropriately to avoid spillage. The collected sample should be delivered to the laboratory for analysis as soon as possible. 

Normal results:

The reference range for ALA in urine is as follows:

• <1 year: ≤10 nmol/mL (nanomoles/millilitre)
• 1-17 years: ≤20 nmol/mL
• ≥18 years: ≤15 nmol/mL

The reference range of porphobilinogen in urine is 0-8.8 µmol/L.

The reference range for porphyrins in urine is as follows:

• Coproporphyrins: 50–160 mg/24 hours
• Uroporphyrins: Up to 50 mg/24 hours

Abnormal results:

Abnormal results indicate that the individual has a higher than normal amount of porphyrins in the urine. This confirms the presence of porphyria. The doctor may order more tests to confirm the diagnosis and find the type of porphyria the individual has.

If the results show a decreased level of porphyrins (as compared to the reference range), then this could indicate liver disease or hepatitis.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.