SDMA

A raised SDMA points towards reduced kidney filtration, but it is a starting point for a conversation, not a diagnosis on its own. The International Renal Interest Society (IRIS) treats a persistent SDMA above the reference interval as consistent with chronic kidney disease, and uses it alongside creatinine to stage the disease (IRIS, 2023).

Two cautions matter. First, a single high value should be confirmed on a repeat sample, ideally with the pet well-hydrated and after a light fast, because transient factors can nudge it. Second, SDMA reflects filtration in general — an acute kidney insult, dehydration, or reduced blood flow to the kidneys can raise it too, so the surrounding picture (urine concentration, creatinine, phosphorus, blood pressure, clinical signs) is what turns a number into meaning.

The pattern that earns the most attention is a steady upward drift across several tests, even while values remain inside the reference range. A dog moving 9 → 11 → 13 µg/dL over a year has a normal result every time, yet the trajectory is the early footprint of declining function — exactly the kind of signal this marker exists to catch.

A normal SDMA is reassuring about filtration, and a low value has no recognised clinical significance to worry about. It does not, by itself, rule out every kidney problem — a pet losing protein through the kidneys can have normal filtration markers — which is why urine tests (concentration and the urine protein:creatinine ratio) are read alongside it. Think of a normal SDMA as one strong, early-warning instrument on the dashboard, not the whole panel.

Chronic kidney disease (CKD) is the condition SDMA was designed to catch early, and it is common — particularly in older cats. The value of tracking SDMA over time is that CKD is a slope, not an event: function is lost gradually, and the earlier a downward trend is recognised, the more can be done to slow it (diet adjustment, phosphate control, blood-pressure management, addressing proteinuria).

Plotted over a pet's life, SDMA typically sits flat for years, then begins a slow, sustained climb as filtration reserve is used up. Seeing that inflection while the pet is still bright and eating well is what changes outcomes, because the interventions that slow CKD work best before the kidneys are heavily damaged. This is why a longitudinal view — the same marker, same pet, many readings — outperforms any one-off "is it normal?" check.

SDMA is used the same way in both species and shares the same broad reference interval (up to roughly 14 µg/dL), so the interpretation transfers well. The clinical emphasis differs: CKD is especially prevalent in older cats, where SDMA has become a routine part of senior screening, and feline creatinine is easily masked by muscle loss — an ageing, thinning cat can have a "normal" creatinine while filtration falls, so SDMA's earlier sensitivity is particularly valuable there (Hall et al., 2015). In dogs the same early-warning logic applies, with breed and age shaping how aggressively a rising trend is pursued.

SDMA is measured from a routine blood sample, usually as part of a chemistry panel or a senior wellness profile; no special preparation beyond the normal light fast and good hydration is needed. It is reported in µg/dL in most UK and US labs. Values can be modestly affected by hydration and by laboratory method, so — as with every marker — the trend on one lab's assay is more informative than comparing a single figure across different laboratories. Always read your pet's result against the reference range printed on that report.

If your pet's SDMA is raised or rising, the constructive next steps are a conversation with your veterinary surgeon and, usually, a repeat test with a urine sample to build the fuller kidney picture. None of this is cause for alarm on a single reading — the strength of SDMA is precisely that it buys time. Tracking it alongside creatinine, phosphorus and urine concentration, and watching the direction of travel, is how an early signal becomes an early, effective plan.