Doctor's Data · Via Nordic Laboratories · Blood Draw UK-Wide
Eight plasma markers that measure methylation capacity directly — not inferred from genetics, not estimated from symptoms. The biochemistry of what your methylation cycle is actually doing right now.
The Eight Markers
The Methylation Profile Plasma measures the key metabolites of the one-carbon cycle directly in plasma — capturing the actual functional state of your methylation pathway, not a genetic prediction of what might be impaired.
The starting point of the methylation cycle. Low methionine signals inadequate cycle input — from poor dietary protein, impaired absorption, or upstream deficiency.
The active methylating molecule — donates methyl groups to DNA, neurotransmitters, hormones, phospholipids, and detoxification reactions. Low SAM means reduced methylation capacity across every downstream process.
Produced after SAM donates its methyl group. SAH accumulates when the cycle stalls — and critically, elevated SAH inhibits further methylation even when SAM appears adequate.
The single most clinically important number on this panel. A falling ratio reveals methylation insufficiency before SAM alone appears low — the ratio is more sensitive than either marker in isolation.
The metabolic crossroads — either remethylated back to methionine (requires B12, folate, MTHFR) or transsulphurated to cystathionine (requires B6). Elevated homocysteine signals a bottleneck and drives vascular and cognitive risk.
Elevated cystathionine indicates CBS enzyme impairment or B6 insufficiency. Important in the MTHFR context — CBS variants alter the balance between remethylation and transsulphuration.
Downstream of cystathionine — the precursor to glutathione, the body's primary antioxidant. Low cysteine signals impaired transsulphuration and reduced detoxification reserve.
Elevated adenosine is produced when SAH hydrolase runs in reverse — a key signal of cycle stagnation. Adenosine also has independent anti-inflammatory and neuromodulatory roles.
A ratio above 4.5 indicates adequate methylation capacity. Below 4.5, methylation reactions across the body begin to stall — affecting DNA repair, neurotransmitter synthesis, hormone detoxification, and immune regulation simultaneously. The ratio declines before either SAM or SAH individually moves outside reference range, making it the most sensitive early indicator on the panel.
Functional vs Genetic Testing
Genetic MTHFR testing tells you whether you carry the C677T or A1298C variants. What it cannot tell you is whether those variants are actually impairing your methylation — because gene expression is not destiny.
MTHFR variants reduce enzyme efficiency, but the clinical impact depends on B2 (riboflavin) status, B12, folate, the presence of other SNPs, dietary intake, gut absorption, and accumulated lifestyle load. Two people with identical C677T homozygous genotypes can have entirely different plasma methylation profiles.
Plasma methylation markers measure the output of the cycle — what the whole system is actually producing — rather than a single genetic bottleneck within it. That is clinically more useful for guiding intervention.
A person with no MTHFR variants can have a depleted methylation index. A person with compound heterozygous MTHFR can have a normal SAM:SAH ratio if cofactor status is adequate. Genetics sets the ceiling; function tells you where you're actually standing.
Standard bloods often include serum homocysteine. That is useful but incomplete — the plasma methylation panel adds SAM, SAH, the methylation index, cystathionine, cysteine, and adenosine, giving a picture of why homocysteine is elevated and where in the cycle the problem sits.
If you have not previously been tested for MTHFR variants, a buccal swab SNP screen can be run alongside the plasma panel. Covers C677T and A1298C — the two clinically significant variants — via Nordic Laboratories.
This confirms whether a genetic bottleneck exists, while the plasma panel tells you its functional impact. Used together, they give a complete picture.
The SNP screen is a low-cost screening flag — not a clinical endpoint. A positive C677T result tells you enzyme efficiency is reduced. It does not tell you by how much, in what context, or whether intervention is needed now.
The SNP screen is best used as an entry point that leads to functional testing when the result is positive, or when symptoms persist despite a negative genetic result.
We do not recommend genetic testing as a standalone without functional follow-up.
Clinical Indications
Methylation touches every major biochemical system. These are the presentations where plasma methylation testing most commonly adds clinical clarity.
Mandatory folic acid fortification of UK flour came into effect in 2024. For individuals carrying MTHFR variants — estimated at 40–60% of the population — synthetic folic acid cannot be efficiently converted to the active methylfolate form. Unmetabolised folic acid (UMFA) may compete with methylfolate at the folate receptor, potentially worsening methylation status. If you are concerned about your response to fortification, plasma methylation testing provides direct evidence of current status. Read the full analysis →
The Process
Doctor's Data Methylation Profile Plasma is ordered via Nordic Laboratories. A venous blood draw is required — available through Bloods and Beyond across the UK with home phlebotomy.
Contact me to discuss whether this test is appropriate for your situation. A brief intake exchange helps confirm clinical fit before ordering.
Test kit is ordered via Nordic Laboratories and dispatched to your address. Includes all collection materials and prepaid return packaging.
A Bloods and Beyond phlebotomist visits your home or workplace for venous collection. Fasted morning draw recommended. Fee: £55–£95 depending on location.
Sample is processed at Doctor's Data. Results typically returned within 10–14 working days.
60-minute review of your methylation panel with full clinical interpretation — the SAM:SAH ratio in context of your history, symptoms, and any other functional test data.
Written recommendations covering targeted nutritional support, cofactor priorities, dietary changes, and where indicated, the case for additional functional testing.
Investment
All fees are transparent and confirmed before ordering. Lab fees are passed through at cost with no markup.
| Item | Fee | Notes |
|---|---|---|
| Methylation Profile Plasma (Doctor's Data) | £219 | Via Nordic Laboratories. Kit dispatched to your address. |
| Home blood draw (Bloods and Beyond) | £55–£95 | Phlebotomist to your location. Price varies by postcode. |
| Results consultation (60 min) | £145 | Full clinical interpretation, written protocol. |
| MTHFR SNP Screen (optional add-on) | £83.50 | Buccal swab. C677T and A1298C. Via Nordic Laboratories. |
| All-in total (without SNP) | From £419 | Lab + draw (lower bound) + consultation. |
If you have existing OAT, DUTCH, GI-MAP or blood chemistry results, the methylation panel can be interpreted in that context — adding significant clinical depth to what you already know. Mention this when you enquire.
Related Reading
The methylation panel sits within a larger clinical picture. These resources provide the context.
Stephen Duncan FDN-P MSc BSc · Edinburgh & UK-Wide
This test is particularly relevant if you've been told you carry MTHFR variants, have elevated homocysteine, or are concerned about folic acid fortification. Get in touch to discuss whether it fits your clinical picture.