|
Test ID: Delta aminolevulinate (spot urine)
|
|
Delta aminolevulinate (spot urine)
|
|
Delta aminolevulinate (spot urine)
|
|
Useful For
|
The measurement of delta aminolevulinate in urine is used in the investigation of suspected acute porphyrias, particularly in children.
|
|
Method name and description
|
Spectrophotometric assay following a reaction with Ehrlich Reagent
|
|
Clinical information
|
The porphyrias are a group of disorders related to enzyme disturbances affecting the biosynthesis of haem. They can be inherited or acquired, and are often classified as either acute or cutaneous porphyrias.
The acute porphyrias can present with a a variety of non-specific signs and symptoms including abdominal pain, hyponatraemia, neuropathy, and vomitting. Acute porphyrias are characterised by the increased urinary excretion of delta aminolevulinate and porphobilinogen, so the measurement of these porphyrin precursors can be useful in the investigation of suspected cases.
Acute porphyrias rarely present during childhood. Delta aminolevulinate should be measured in suspected paediatric cases to exclude a rare form of porphyria due to a deficiency of porphobilinogen synthase (aminolevulinic acid dehydratase).
|
|
Aliases
|
Delta aminolevulinic acid
5-Aminolevulinate
5-Aminolevulinic acid
ALA
|
|
|
Specimen type / Specimen volume / Specimen container
|
Specimen type: spot urine.
Specimen Volume: at least 10 mL.
Specimen container: suitable plain urine collection container and must be covered against light and transported to the laboratory as soon as possible.
|
|
Collection instructions / Special Precautions / Timing of collection
|
Collect the urine sample in plain container without any preservatives and protected from light.
In case of an acute attack, spontaneous urine should be collected approximatly 2–4 hours after onset of the symptoms.
|
|
Relevant clinical information to be provided
|
Presenting signs and symptoms
|
|
Storage and transport instructions
|
Urine samples may be stored for up to 1 day at 20-25°C.
Urine samples may be stored for up to 3 days at 2-8°C.
Urine samples may be stored for up to 1 month frozen at -20 °C. The sample should not be thawed till analysis.
Samples should be transported according to their storage conditions.
|
|
Specimen Rejection Criteria
|
Insufficient sample.
Sample collected into a container with preservatives.
Sample not protected from light.
|
|
|
Biological reference intervals and clinical decision values
|
|
[µmol/mmolCreatinine]
|
|
Negative (cut-offs)
|
Borderline
|
Positive
|
|
< 2.60
|
2.60–6.91
|
> 6.91
|
|
|
Factors affecting test performance and result interpretation
|
False negative results may occur if the urine is collected too long after an acute attack.
Excessively dilute urines may produce unreliable results.
Alcohol consumption may increase delta aminolevulinate excretion.
Lead toxicity can increase delta aminolevulinate excretion.
|
|
Turnaround time / Days and times test performed / Specimen retention time
|
Turnaround time: 5 working days.
Days and times test performed: Sunday to Thursday.
Specimen retention time: 3 days.
|
|
|
