Home Glucose Curve for Cats: 12 Hours, 7 Readings

A home glucose curve is 7 finger-stick readings taken every 2 hours across 12 hours, on a day the cat eats and is injected on schedule. It shows what the insulin actually does in that cat's body, which a single clinic reading cannot. Run it on a normal day and the numbers mean something; run it around a shifted meal and they do not.

Why the clinic number lies

Stress raises blood glucose in cats fast and hard. A cat that fights the carrier can go from 90 mg/dL at home to 280 mg/dL in the parking lot, and a cat that sulks in a cage can sit above 300 mg/dL for the whole visit. Vets call it stress hyperglycemia; it is the most common reason a healthy cat gets a false diabetes label or a well-regulated cat gets an unnecessary dose increase.

Two things separate stress from real disease. Fructosamine reflects average glucose over the previous 1 to 3 weeks and barely moves with a bad car ride; a normal fructosamine with a high spot reading means stress. Urine glucose is the second check: glucose spills into urine only after blood has been above roughly 180 to 220 mg/dL for hours, so a negative urine test alongside a 300 mg/dL reading points to stress.

Equipment that actually works

You need a human glucometer (any pharmacy brand, 20 to 40 dollars), matching strips, lancets of 26 to 28 gauge, and a warm damp cloth. Cat blood volumes are small: a 0.3 microliter drop is enough, and a whole curve uses under 3 microliters, which is why a cat does not become anemic. Pet-specific meters cost 3 to 5 times more and are not more accurate in the 50 to 300 mg/dL range.

Keep a paper log of time, food, units, glucose, and behavior; meters store 200 to 500 readings but the vet reads the log.

Ear margin technique in 4 steps

The ear margin is the standard site, on the outer edge of the pinna. Warming it for 30 to 60 seconds with a damp cloth dilates the vessels and roughly halves failed pricks.

• Wrap the cat in a towel, head out, and work on a waist-height table.
• Hold the ear flat against your palm, press the lancet at a 90 degree angle to the skin surface, and release without hesitating.
• Touch the strip edge to the drop sideways. Scooping from above smears the blood across the fur.
• Press a dry cotton ball on the spot for 15 to 20 seconds, then give a treat. Two treats per reading keeps most cats cooperative by reading 4.

Alternate ears so no spot takes 3 pricks in a day, and if 2 attempts fail, warm the ear again instead of stabbing harder.

The 12 hour schedule

Start at the morning insulin dose, not at breakfast: reading 1 goes just before the injection and food, giving the fasting baseline. Then every 2 hours: 7 readings at hours 0, 2, 4, 6, 8, 10, and 12. Feed and inject exactly as on a normal day, at the normal time, with the normal amount.

The lowest point, called the nadir, usually lands 4 to 8 hours after a dose with glargine and 2 to 6 hours with a faster-acting insulin such as Vetsulin. The nadir matters more than the starting number: a cat starting at 380 mg/dL that drops to 90 mg/dL is on too much insulin, not too little, and the pre-dose reading alone would suggest the opposite.

Clock hour	Action	Target glucose	Note
Hour 0	Prick, then feed and inject	150 to 300 mg/dL	Fasting baseline
Hour 2	Prick only	120 to 280 mg/dL	Rise or fall both normal here
Hour 4 to 6	Prick, watch for nadir	100 to 250 mg/dL	Most common nadir window
Hour 8	Prick only	100 to 280 mg/dL	Rising again is expected
Hour 10 to 12	Prick, next meal due	150 to 300 mg/dL	Under 150 means reduce dose

Targets for a treated cat are usually 100 to 300 mg/dL through the day with a nadir above 80 mg/dL; some vets accept 80 to 150 mg/dL in a cat eating well. Chasing numbers under 80 buys little and adds hypoglycemia risk.

Reading the curve: 4 patterns

A flat curve that never drops below 300 mg/dL means the dose is too low or the insulin has lost potency; check the vial date before increasing anything. A deep curve that drops from 400 to 70 mg/dL and climbs back means too much insulin, and the fix is a smaller dose, not a snack. A curve that bottoms out early, at hour 2 to 3, points to a short-acting insulin being used where a longer one belongs. A curve with one wild spike is usually a missed meal or a fur shot, where the needle passed through both skin layers.

Run a curve every 7 to 14 days during adjustment, then every 3 to 6 months, and never within 3 days of a dose change.

When the number is under 60 mg/dL

Under 60 mg/dL is hypoglycemia and under 40 mg/dL is an emergency even if the cat looks fine: wobbling, head pressing, dilated pupils, drooling, then seizures or coma. Act now, without waiting for a call back.

• Rub a teaspoon of honey, corn syrup, or glucose gel on the gums and inner lip. Do not pour liquid into the mouth of a cat that is not swallowing.
• If the cat can swallow, offer 1 to 2 tablespoons of its normal food, or a high-carb treat, and let it eat.
• Recheck glucose in 15 minutes. If it is still under 60 mg/dL, repeat the sugar and call the clinic.
• Do not give the next insulin dose until the vet has seen the numbers, even if the cat recovers fully in 20 minutes.

Record the time, the recheck value, and what the cat ate; that lets the vet cut the dose correctly, usually 10 to 25 percent, instead of guessing.

Keeping the data usable

Photograph the meter screen at each reading, or write the number down before you clean up. Owners routinely lose 2 of 7 readings to memory, and 5 points make a much weaker curve than 7. A curve with notes beats a tidy table with no context. Blood pressure, which is a separate measurement and the other half of the monitoring picture, is covered in blood pressure measurement.

Run the curve in a quiet room, never on a day with visitors or a new food; stress moves glucose by 50 to 150 mg/dL. The setup in a cat-friendly home room by room helps, and vaccine days should not double as curve days (vaccine calendar).

Frequently asked