Methylmalonic acid (MMA) blood test

Your doctor will ask you to get this blood test done if he/she suspects that you have a vitamin B12 deficiency. You may not experience the symptoms of the deficiency immediately as they develop gradually. Most common symptoms of vitamin B12 deficiency include the following:

• Numbness in feet and hands
• Tingling sensation in extremities
• Inflammation or swelling of the tongue
• Weakness and unexplained tiredness
• Anaemia
• Difficulty thinking and reasoning
• Memory loss

This test may also be suggested if the doctor suspects that you have methylmalonic acidaemia, a rare genetic condition in which the body is not able to metabolise certain proteins and fats. Symptoms of the disorder begin to appear very early, usually during infancy, and include lethargy, dehydration, vomiting, seizures and delayed development.

No fasting or prior preparations are needed. Make sure to inform your doctor if you are taking any routine medications or health supplements.

A trained healthcare provider will take a blood sample from a vein in your arm using the following procedure: 

• The healthcare provider will wrap an elastic band (a tourniquet) around your upper arm. It helps to slow down the blood flow and locate the appropriate vein from which the sample can be drawn. 
• Once a suitable vein is located, a technician will clean the skin above it using an antiseptic solution. This is done to minimise the risk of any infection. 
• He/she will then insert a needle into the vein. You may feel a pricking or piercing sensation when the needle is being inserted. A small tube attached to the needle helps in the collection of the required amount of blood.
• After the required amount of blood is drawn, the tourniquet will be released, and the needle will be removed. 

The entire test takes only up to a few minutes. If you tend to get anxious about needles, communicate this to your healthcare provider so that they can make you relax before the test is done. 

The area where the needle is inserted may be bruised for a while after the test but it will heal eventually.

Normal results:

The normal MMA range in blood is 53-376 nmol/L.

Normal results indicate that you may not have a vitamin B12 deficiency, and the symptoms could be attributed to some other health conditions.

Abnormal results:

If the test is done for an infant, abnormally high MMA levels might be indicative of methylmalonic acidemia. 

An abnormally high level of MMA could also be due to the following:

• Vitamin B12 deficiency
• Kidney diseases
• Pregnancy

In case of kidney diseases, MMA is not excreted properly in urine due to which it accumulates in the blood.

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.