Amino Acids Blood Test

Your doctor may order this test if they observe the following signs and symptoms associated with faulty amino acids metabolism in your body: 

• Seizures
• Inability to thrive
• Lethargy
• Developmental delay
• Movement disorders
• Liver dysfunction in new-borns

This test may also be ordered if your present with the following symptoms or conditions:

• Mental retardation
• Liver cirrhosis
• Ectopia lentis (displacement of the lens of the eye)
• Arthritis of the spine and joints
• Prostate and kidney stones

You may have to fast before this test. If the test is being done for a newborn, the baby should not be fed for four hours before the test. 

For assessment of a particular amino acid, your doctor may recommend a diet rich in that amino acid prior to the test. You may maintain moderate hydration before the fasting period.  

Amino acid concentration levels may be affected by various factors such as:

• Sleeping pattern
• Drugs such as amphetamines, norepinephrine, levodopa, almost all antibiotics, and intravenous therapy
• Age
• Time of sample collection 
• Pregnancy 

So, please share your complete medical history with your doctor before the test. 

A lab technician will draw a blood sample from a vein in your arm. After the test, you may experience mild pain at the site of the injection - it will go away on its own. 

In newborns, the sample is collected through a heel prick.

Normal results:

The reference ranges of different amino acids tested commonly in the blood are mentioned in Table 1. 

Table 1: References ranges of some important amino acids in the blood 

Normal values may vary slightly among different laboratories. 

Abnormal results:

Abnormal results are indicated by either a decrease or an increase in the total levels of the amino acids. 

A decrease in the blood amino acids levels may indicate: 

• Overproduction of hormones in the cortex of the adrenal gland 
• Huntington's chorea (brain disorder characterised by involuntary movements)
• Phlebotomus fever (infection caused by the bite of a sand-fly)
• Nephrotic syndrome (kidney disorder marked by excretion of protein in the urine)
• Rheumatoid arthritis
• Hartnup disease (characterised by skin rashes that occur due to an inability to absorb amino acids)

Elevated total amino acids in the blood may be seen in the following conditions: 

• Seizures
• Acidosis
• Kidney failure
• Encephalopathy (brain disease) 

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.