Homocysteine, Methylmalonate, and 2-Methylcitrate Panel, Dried Blood Spot
This dried blood spot panel measures homocysteine, methylmalonate, and 2-methylcitrate, substances that may increase when vitamin B12 or related metabolic pathways are impaired. It is used to help evaluate possible methylmalonic acidemia, homocystinuria, and related inherited metabolic disorders.
["Abnormal results may indicate a vitamin B12-related or inherited metabolic disorder, but they must be interpreted and confirmed by your healthcare team."]
Key facts at a glance
- LOINC
- 100765-7
- Short code
- Hcys+Me-Malonate+2Me-citrate Pnl DBS
- Synonyms
- Hcys+Me-Malonate+2Me-citrate Pnl DBS
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 20
- Ref high
- 400
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82670
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What the test measures
Homocysteine is an amino acid linked to several metabolic processes. Methylmalonate is a compound that can accumulate when methylmalonyl-CoA metabolism is disrupted, including with vitamin B12 deficiency. Elevated 2-methylcitrate can support evaluation for methylmalonic acidemia.
How the test is performed
A small blood sample is collected and placed on a filter card, known as a dried blood spot. The card is sent to a laboratory, where the three substances are measured using specialized laboratory methods.
Why the test may be ordered
This panel may be used in newborn screening or when an infant or child has unexplained developmental delay, feeding problems, poor growth, unusual blood counts, or symptoms suggesting a metabolic disorder. It may also be ordered when a family history or screening result raises concern for an inherited metabolic condition.
Understanding the results
Results can be affected by vitamin B12 deficiency, medications, diet, prematurity, and other clinical factors. An elevated result does not by itself establish a diagnosis; your clinician may recommend repeat testing and additional blood, urine, or genetic studies.
Reference range
Premenopausal: 20-400 pg/mL; Postmenopausal: <30 pg/mLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical significance
Short name
Methylmalonic acidemia metabolic screening panel
Frequently asked questions
What conditions can this panel help evaluate?
Does an abnormal result mean my child has a metabolic disorder?
What happens if the panel is abnormal?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy