Methylmalonic Acid (MMA) urine test

Your doctor may order this test if he/she observes symptoms of:

• Neuropathy (damage to the nerves)
• Methylmalonic acidaemia (commonly diagnosed in infants) 

Methylmalonic acidaemia is a rare genetic condition in which the body is unable to metabolise certain proteins and fats. The symptoms of methylmalonic acidaemia can be seen early during infancy. Some of the symptoms are:

• Lethargy 
• Recurrent vomiting
• Difficulty in breathing
• Developmental retardation 
• Chronic kidney disease 
• Dehydration 

This test is also ordered to people who show symptoms of vitamin B12 deficiency - increased methylmalonic acid in urine is an early indicator of vitamin B12 deficiency. Some notable symptoms of vitamin B12 deficiency include:

• Numbness in hands or feet
• Confusion 
• Frequent mood swings
• Irritability 
• Difficulty sleeping
• Fatigue
• Frequent headaches 

A methylmalonic acid urine test may be preferable over the methylmalonic acid blood test because methylmalonic acid is more stable and concentrated in the urine than blood. It is also less invasive than a blood test.

You will be asked to refrain from consuming alcohol before you get this test done, as it can interfere with the results. 

Notify your doctor if you are taking any routine medications or health supplements.

This test can be done on a 24-hour urine sample or a random urine sample. You will be provided with a special container to collect the sample. 

A random urine sample is a single sample that can be collected at any time of the day. 

A 24-hour urine sample involves the collection of multiple samples throughout the day. Following is the procedure for collection of a 24-hour urine sample:

• Begin collecting the sample in the morning. 
• Discard the first urine of the day, but note this time as the start of the collection process.
• From then on, all the urine has to be collected in the container for the next 24 hours. 
• You must label the container appropriately with your name, date and time of collection of the sample. 

Between sample collection, make sure to place the urine container in a cool area. You may place it on ice or in the refrigerator. After the sample has been collected, submit the container to the laboratory for analysis.

When collecting a urine sample from an infant, be sure to clean the area around their urethra. Then, place the urine collection bag (provided by the lab) on the infant to collect the sample. Be sure to avoid any spillage. Hand over the sample to the laboratory.

Results of this test are expressed in the form of urine MMA-creatinine ratio. Your doctor may order a urine creatinine test along with this test.

Normal results:

The reference range for this test is 0.0-3.6 mmol/mol CRT (millimoles per mole of creatinine).

Normal results indicate that you may not have a vitamin B12 deficiency and the symptoms could be attributed to another condition. Further testing may be performed to determine the cause of your symptoms. 

Abnormal results:

An elevated level of methylmalonic acid in the urine could be indicative of vitamin B12 deficiency. It may also be indicative of methylmalonic acidaemia.

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.