Blood pressure in cats is measured with one of two devices, and the two do not agree: Doppler and oscillometric readings commonly differ by 10 to 20 mmHg on the same cat. A single reading is close to useless, because stress alone can add 20 to 30 mmHg. The workable protocol is a quiet room, a correctly sized cuff, and 5 readings averaged after discarding the first.
Why cats need blood pressure checks at all
Hypertension in cats is almost always secondary, driven by chronic kidney disease, hyperthyroidism, or hyperaldosteronism, and it damages the same organs quietly: the retina, the kidney, the heart, and the brain. It is one of the few things in senior cat medicine that is cheap to screen for and treatable. Every cat over 10, and every cat with CKD or an unchecked thyroid, should have a reading at least once a year.
The damage is often how it is found. Sudden blindness from retinal detachment, a new heart murmur, or protein in the urine can all be the first visible sign of a pressure that has been high for months.
Doppler versus oscillometric
Doppler uses a crystal over the artery (usually the coccygeal artery under the tail, or the median artery on the forelimb) and a cuff proximal to it. It gives systolic pressure only, and it needs someone to hear the return of flow, which takes practice. Its advantage is that it works on small, hairy, wriggling cats and gives a consistent systolic number.
Oscillometric machines inflate and measure oscillations, and report systolic, diastolic, and mean. They are easier to use but less reliable in cats under about 4 kg, in cats with arrhythmia, and when the cat is shivering. Mean arterial pressure is often the most trustworthy number they produce. Whichever device your clinic uses, trends matter more than a single visit.
The 5 reading protocol
Take readings 30 to 60 seconds apart. Discard the first, which is almost always the highest, then average the next 5. If the spread between the highest and lowest of those 5 is more than 20 mmHg, the cat is not settled and the series should be repeated after another 5 minutes. Report the average, not the best-looking number.
| Systolic (mmHg) | Category | Typical action |
|---|---|---|
| Under 150 | Normal | Recheck in 12 months |
| 150 to 159 | Borderline | Repeat in 2 to 4 weeks |
| 160 to 179 | Hypertensive | Look for target organ damage, treat if present |
| 180 and above | Severe | Treat and recheck in 1 to 2 weeks |
Cuff size decides the result
The cuff width should be about 30 to 40 percent of the limb circumference, and the cuff should sit at heart level. Too narrow and the reading runs high by 10 to 15 mmHg; too wide and it runs low. Most clinics stock 3 or 4 cuff sizes for a reason, and a cat that measures 160 on a cuff that is too small may be normal.
Place the cuff on the tail base or the forelimb, never over a joint, and keep the limb relaxed. A limb held in the air reads higher than one resting on a table. If you are using the tail, the cat can stay in sternal position, which most cats tolerate better than lateral restraint.
White coat effect and how to beat it
Clinic stress adds roughly 20 to 30 mmHg. Let the cat sit in the room for 5 to 10 minutes before the cuff goes on, in a carrier with the door open, and do the first readings with the owner present and quiet. No talking during the measurement, no restraint beyond a towel, and no other cats in the room.
Home measurement is the honest option when clinic numbers keep coming back high without organ damage. A vet can lend or sell a Doppler unit, and a 3 day series of 5 readings each morning is more informative than any single visit. Record the device, cuff size, and limb, because switching devices mid-series creates fake trends. If you are tracking a kitten's growth alongside this, the kitten weight tool keeps the numbers in one place.
What high pressure does, and what treatment looks like
Target organ damage shows up as retinal hemorrhage or detachment (sudden blindness), proteinuria and faster kidney decline, left ventricular thickening, and in severe cases seizures or epistaxis. A cat with systolic 180 and a detached retina needs treatment the same day, not next month.
Amlodipine at 0.625 mg per cat once daily is the usual first step, with a recheck in 7 to 14 days; some cats need 1.25 mg. Do not add an ACE inhibitor just for pressure. If amlodipine alone does not hold the number, the next questions are sodium, thyroid, and kidney status rather than a bigger dose. Never start or change these drugs without a vet, and never stop amlodipine abruptly.
When to call the clinic today
Sudden blindness, pupils that stay dilated, bleeding inside the eye, a seizure, or a nosebleed in an older cat all justify a same-day call. So does a systolic reading of 180 or more with any of those signs. For a cat that has been stable on amlodipine, a jump of 20 mmHg or more from its own baseline is also worth a call.
Cats with kidney disease are the group most likely to be hypertensive, and the signs overlap with those of a urinary blockage, listed under urinary blockage signs. If the presentation includes head tilt or balance loss instead, the differential shifts, and vestibular disease covers that pattern. Bring your reading log to the appointment; it changes the conversation from one number to a trend.
Frequently asked
What is a normal blood pressure for a cat?
A systolic reading under 150 mmHg is considered normal, and 150 to 159 is borderline. From 160 to 179 the cat is hypertensive and should be checked for target organ damage such as retinal change or protein in the urine. At 180 and above the risk is high and treatment is usually started, with a recheck in 1 to 2 weeks depending on the drug used.
Why do two blood pressure readings differ so much?
Because the methods measure different things and stress moves the number. Doppler reports systolic only, while oscillometric devices estimate systolic, diastolic, and mean, and the two can differ by 10 to 20 mmHg on the same cat. Anxiety can add another 20 to 30. That is why a protocol discards the first reading, averages 5, and repeats the series when the spread exceeds 20 mmHg.
Can I measure my cat's blood pressure at home?
Yes, with a Doppler unit and some practice, and it is the best answer to white coat effect. Let the cat settle for 5 to 10 minutes, use a cuff at 30 to 40 percent of limb circumference at heart level, take 5 readings 30 to 60 seconds apart, and average them. Keep the same device, cuff, and limb across the series, and bring the log to every appointment.