By The Pawline veterinary teamVeterinary-reviewed by Alastair Greenway, BVM&S MRCVS · 25 July 2026
Reference range · µg/L
7.517
Reference
7.5–17
Direction
Both unusually high and low values carry meaning.
This is the conventional reference interval. Your pet’s own report may print a slightly different range — always read the value against that. Sign in to see your pet’s value on this strip.
Folate is a vitamin absorbed in the upper gut, so reading it alongside B12 (absorbed lower down) helps pinpoint where in the digestive tract a problem sits. Both extremes carry meaning, and the pattern of the two vitamins together is more useful than either alone.
Folate (vitamin B9) is absorbed high up, in the upper small intestine (the duodenum and jejunum) — a different location from where B12 is taken up, in the lower gut. That geographical difference is exactly what makes folate useful: by comparing folate and B12, a vet can often work out which part of the intestine is affected, turning two vitamin levels into a rough map of the gut.
Folate is absorbed in the upper gut and B12 in the lower gut, so the two read together help localise where an intestinal problem sits.
Reading the folate/B12 pattern
Folate is best interpreted with B12, because the combination localises disease:
Low folate points to disease of the upper small intestine (impaired absorption there).
Low B12 points to the lower small intestine or pancreas.
Both low suggests diffuse, generalised small-intestinal disease.
High folate with low B12 is a classic pattern of small-intestinal dysbiosis — an altered microbiome, where bacteria in the upper gut produce extra folate while consuming B12.
So a folate value rarely means much in isolation; its power is in the pattern it forms with B12.
Reading a high or low result
A low folate on its own suggests reduced absorption in the upper gut (chronic intestinal disease) or, rarely, poor dietary intake. A high folate most often reflects the dysbiosis pattern above (bacterial overproduction), or supplementation. Because both directions are informative, folate is genuinely a two-way marker — unlike B12, where the low end carries most of the message.
In chronic disease
In chronic gastrointestinal disease, tracking folate alongside B12 over time helps monitor how widespread the problem is and how it responds to treatment. A shifting folate/B12 pattern can reflect changing disease location or a changing microbiome, information a single measurement cannot provide. Where dysbiosis is driving a high folate, following it as the gut is treated shows whether the microbial balance is recovering.
Cat vs dog
Folate is interpreted the same way in both species, with feline reference ranges running slightly higher. The folate/B12 mapping logic applies equally to dogs and cats, and both species develop the chronic intestinal diseases and dysbiosis that these vitamins help characterise. As always, the two are read together rather than apart.
How it's measured
Folate is measured from a fasted blood sample at a laboratory running the gastrointestinal panel, reported in µg/L (or nmol/L), almost always paired with B12 (and often TLI and pancreatic lipase). Haemolysis can raise the reading, so clean collection matters. Read the value against your own report's range — and, crucially, alongside the B12 result.
What to do next
Because folate earns its meaning from the pattern it forms with B12, the useful step is to interpret the two together with your vet, using them to localise gut disease and to flag dysbiosis. Where a deficiency or a dysbiosis pattern is found, it guides both further investigation of the gut and, in the case of low vitamins, direct supplementation.
Reference ranges reflect conventional laboratory intervals. Always interpret against your own lab's printed range and your veterinary surgeon's judgement. A brighter optimal band is shown only where a published guideline defines one, and it is cited.
This page is educational and is not a diagnosis. Lab results are interpreted in the full clinical context by your veterinary surgeon; a single value rarely tells the whole story.
