Reference Ranges: Why Your Pet's Report Shows a Range

A reference range is the span of results usually seen in healthy animals of the same kind, measured by the same method. It is printed next to each result so that you and your vet can see at a glance whether a number sits inside or outside it. A result outside the range is a clue and not a diagnosis, and a result inside it is not a promise of health.

Where does a reference range come from?

Labs set ranges by measuring many healthy animals and noting where most of their results fall. Because a few healthy animals always fall just outside, the range is a guide to what is usual and not a wall between health and disease. It also depends on how the test was done, so the range printed on your report belongs to the method and instrument that produced your result.

Why do ranges differ between animals?

A dog, a cat, a horse, a cow and a buffalo are different bodies, and many results are normal for one and unusual for another. A puppy, an adult and an old dog also differ, and some breeds have their own habits. Pregnancy, heavy exercise, fear, a recent meal and dehydration can all move a result without any disease. This is why a range copied from the internet, or from a report from another lab, is a poor yardstick. Use the range on your own report, and let your vet judge it for your animal's species, age and condition.

What does "high" or "low" really mean?

Reports often mark results with an arrow or the letters H and L. That flag only says that the number is outside the printed range. It does not say why. A slightly raised result may be nothing, and a result inside the range can still matter if it has changed from last time. A registered veterinarian looks at three things together: how far outside the range the number is, how it fits with the animal's signs, and whether other results point the same way.

Bodies are not constant. Hormones, feeding, stress and time of day change many results from one day to another. A cat that is frightened at the clinic can show a different blood sugar from the same cat relaxed at home. Methods and machines also differ slightly from lab to lab. That is why one value on its own says less than a trend over several tests, and why vets like to repeat a test before acting on a small change.

Which tests show this clearly?

The ideas apply to every test. In a Complete Blood Count (CBC) the counts of red cells, white cells and platelets are compared with ranges for the species. In a Kidney Function Test (KFT) and a Liver Function Test (LFT), the markers of kidney and liver function each have their own range. For tests that vary a lot by species, such as many enzyme and mineral values in cattle and horses, the range shown is the one the lab uses for the species named on your booking, so make sure the species on the report is right.

What should you do with a flagged result?

Do not panic and do not change any medicine or feeding on your own. Take the report to your vet, who will read it together with your animal's signs and history. Ask whether the result is important or only slightly off, whether the test should be repeated, and whether other tests would help. If the report shows the wrong species, age or name, tell the lab at once so that it can correct the report.

Keep each report, because a range is easier to understand across several tests than in one. Reports are stored in My Reports on the website, and you can share them with your vet. A normal result does not always rule out disease, and an abnormal result does not always mean disease, so the vet's reading always comes first.

Read next

For a closer look at how to go through a report with your vet, read How to Read a Lab Report Together With Your Vet. To see how the sample gets to the lab, see Free Home Sample Collection in Bhopal: How It Works.

Testing in Bhopal

The lab at C-200, C Sector, Shahpura, Bhopal confirms the method, sample needs and reporting time when you book, and reports reach you on WhatsApp, email and in your online account. Sample collection is free anywhere in Bhopal. Call or WhatsApp +91 88175 01118 if a report is unclear, and keep your vet in the conversation.