By The Pawline veterinary teamVeterinary-reviewed by Alastair Greenway, BVM&S MRCVS · 25 July 2026
Experimental marker
This marker has no established reference range in dogs or cats yet, so it is read as a trend rather than measured against a threshold.
Klotho is a protective protein, made largely by the kidneys, that links kidney function with inflammation, bone and musculoskeletal health — and lower levels track chronic kidney disease and ageing. It is a research assay with no routine clinical reference range in dogs or cats, so it is surfaced as an emerging signal only.
Klotho is one of the more striking molecules in ageing biology. Produced largely by the kidneys, it acts as a protective, anti-ageing factor: it helps regulate phosphate and vitamin D, restrains inflammation, and supports vascular, bone and muscle health. In laboratory models, losing klotho produces a picture resembling accelerated ageing; boosting it does something closer to the opposite. Because its main source is the kidney, klotho ties kidney health to whole-body ageing in a way few markers do — a connection that makes it genuinely interesting for longevity-minded care.
Klotho is a protective protein made largely by the kidneys, linking kidney function to inflammation, bone and muscle health. Lower levels track CKD and ageing.
Unusually for this library, klotho is a marker where lower is the concern.
Why this is an experimental marker
Klotho sits in the frontier layer at the "experimental" end. It is measured with research assays; there is no routine clinical reference interval in dogs or cats, and no validated cut-off that would let anyone call a value normal or low for an individual pet. So here it is:
read as a trend only on a single assay;
excluded from the in/out-of-range tally and from any health score;
never turned into a finding, a diagnosis, or a prognosis for an individual animal.
Anything more definitive would over-claim.
What a falling trend might mean
Read as a direction, declining klotho is consistent with what the research describes: lower levels track chronic kidney disease and advancing age, and are associated in studies with inflammation and mineral-bone disturbance. Conceptually, as functioning kidney tissue is lost, the body's main klotho source diminishes — which is why klotho is discussed alongside phosphorus and FGF-23, the phosphate-regulating system klotho helps control. But in an individual dog or cat today, a falling klotho is an observation to note, not a result to treat.
What a stable trend might mean
A stable klotho across serial measurements is unremarkable in the current state of knowledge. It should not be read as reassurance about kidney health — that job belongs to the validated markers (SDMA, creatinine, urine concentration and UPC), which remain the basis for any clinical judgement.
Cat vs dog
Klotho biology is conserved across species and has been studied in both dogs and cats in research contexts, but neither has a routine clinical assay or reference interval. The same trend-only, no-threshold treatment therefore applies to both. Should validated intervals be published, this page and the marker's handling in the product will be updated.
How it's measured
Klotho is measured from a blood sample using research-grade assays, reported in pg/mL. Methods differ substantially between laboratories, so only results from the same assay are comparable, and no universal band applies. Any result should be interpreted with your veterinary surgeon as an emerging research measure rather than a clinical test.
What to do next
Klotho is currently a marker to watch and understand, not to act on. Kidney care decisions rest on the validated renal panel; klotho adds an emerging longevity-science dimension to that picture. If tracked, it should be on one laboratory's assay, read as a direction of travel, and interpreted with a clear understanding that veterinary reference ranges do not yet exist.
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.
