Plasma amino acid profile
Why do we do this test?
To diagnose disorders of amino acid metabolism
Specimen Type
Whole blood (EDTA)
Instructions for specimen collection & Patient preparation
Patient should be fasting.
Adults : 6 hours
Children >3 years : 4 – 6 hours
Children 1 – 3 years : 3 hours
Infants : just before the next feed
• Sample should be taken without tourniquet.
• At least 2cc volume is needed for analysis.
• Once the sample is transferred to the EDTA tube it should be mixed well.
• Completed request form and the history of the patient including drug history should be accompanied with the properly labeled sample.
Specimen transportation & Processing
Specimen should be transported in ice, to the laboratory immediately.
If transportation takes time, plasma should be separated by centrifugation and separated plasma in a plain tube should be transported in ice.
Separated plasma should be kept in (-20 degrees Celsius) freezer until transfer.
Separated plasma should be deproteinised immediately on reception to the laboratory. Deproteinised plasma is used for analysis.
Specimen storage & stability
Sample should be centrifuged and plasma should be separated immediately. Separated plasma should be deproteinised at the same time on reception to the laboratory.
If any delay in analysis, deproteinised plasma should be stored in -20 degrees Celsius until analysis.
For long term storage, temperature should be -70 degrees Celsius.
Specimen storage duration
Reference Intervals & Target Values
Age specific reference intervals are used for interpretation of plasma amino acid profile.
Critical Limits
Possible Pre-analytical Errors
Haemolysis can elevate some amino acid levels (E.g. glutamate, aspartate, taurine)
Sending post prandial samples
Bacterial contamination
Improper storage conditions
Sending serum samples
Possible Analytical Errors
Certain drugs (antibiotics, anticonvulsants) can alter the amino acid levels.
Available Government Laboratories
Lady Ridgeway Hospital for Children
Recommended turnaround time
2 days to 1 week

Test Method
High performance liquid chromatography Post column derivatization with Ninhydrin



Last Updated : 2020-09-14 05:03:00






College of Chemical Pathologists of Sri Lanka

No.112, Model Farm Road, Colombo 08.  Hotline : +94 76 7044871  Email :

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