Senior Cat Panel: 6 Items, 2 Rise Lines, 6 Months

After age 8, bloodwork stops being a yearly formality. Six items, two rise lines, and a fixed 6-month interval catch kidney, thyroid, and liver change 6 to 12 months before the cat looks sick. What owners control is the 4 records kept between visits, and those records turn a normal-looking panel into an early warning.

The 6 items that earn their place

Clinics sell panels in 3 tiers, and the middle one covers a senior cat. Ask for exactly these 6: complete blood count, chemistry with kidney and liver values, total T4, urinalysis with specific gravity, systolic blood pressure, and SDMA if the lab runs it. That is 1 draw, 1 urine sample, and 20 minutes in the room, after a 6 to 8 hour fast with water left down. Repeat the same 6 at the same lab every 6 months; a trend across 3 visits beats 12 one-off markers.

Two rise lines, not one

An elevated value means one of two different things. The first is an absolute line, above the lab's upper limit: creatinine above 1.6 mg/dL, SDMA above 14 µg/dL, ALT above 100 U/L, ALP above 80 U/L, total T4 above 4.0 µg/dL. Any single one, confirmed on a recheck 2 to 4 weeks later, is a workup rather than a wait. The second is a trend line: still inside the range, but climbing. Creatinine from 1.2 to 1.7 over 6 months, ALT from 45 to 90, weight down 5 percent with a steady appetite. A rise of 30 percent or more between 2 panels 6 months apart deserves a call even when both numbers are technically normal.

Why the interval is 6 months and not 12

Kidney values are a late signal. Creatinine stays inside range until roughly two-thirds of nephron function is gone, which is why IRIS treats 1.6 mg/dL as the first hard line and stages upward at 2.8 and 5.0. In a cat losing function slowly, 180 days is the shortest window that reliably shows a move without letting normal variation drown it out. Thyroid follows the same clock: T4 climbs with age, and a 9-year-old at 3.8 µg/dL is inside range but worth a recheck in 6 months. Once a cat is on thyroid or blood pressure medication, recheck at 3 weeks for the dose, 3 months to confirm, then every 6 months with the full panel. Anything prescribed comes from the vet holding those labs, on a written prescription.

The 6 items, their ranges, and the recheck

Item	Usual range	Absolute rise line	Recheck if normal
CBC, hematocrit	30 to 45 percent	above 50 or below 25	6 months
Kidney: creatinine and SDMA	0.8 to 2.0 mg/dL, SDMA 0 to 14 µg/dL	creatinine above 1.6, SDMA above 14	6 months, 3 if rising
Liver: ALT and ALP	ALT 10 to 100 U/L, ALP 10 to 80 U/L	ALT above 100, ALP above 80	6 months, 4 weeks if doubled
Total T4	0.8 to 4.0 µg/dL	above 4.0, or above 3.5 with weight loss	6 months
Urinalysis and specific gravity	USG 1.035 to 1.060	USG below 1.030, or protein on 2 samples	6 months
Systolic blood pressure	120 to 160 mmHg	160 or higher on 2 visits	6 months

The 4 records you keep at home

Four numbers, 2 minutes a week, and the vet gets a curve instead of an impression. Weight: same scale, same time of day, every 14 days, in 10 gram steps; a 5 percent drop over 3 months is a workup trigger. Water: 45 to 60 mL per kg per day, so 180 to 240 mL for a 4 kg cat, and 400 mL a day is a kidney and thyroid question. Urine clumps: 2 to 4 a day is ordinary, 1 or none over 24 hours is a blockage risk and a same-day call. Sleeping respiratory rate: 15 to 30 breaths a minute, counted for 30 seconds on 3 nights, and 2 readings above 30 within a week is a visit.

When 6 months becomes 4 weeks

Shorten the interval when the panel moves in a direction you can name. Creatinine up 0.5 mg/dL inside 6 months, T4 above 4.0, systolic pressure at 160 mmHg, weight down 5 percent in 12 weeks, or urine specific gravity below 1.030 while drinking went up. Add vomiting 2 or more times a week for 3 weeks and the recheck moves to 4 weeks with a urine culture attached. Do not redo the whole panel to answer that question; repeat the 2 or 3 flagged items.

What quietly moves the numbers

Dehydration of 5 percent can push creatinine up 0.2 to 0.3 mg/dL and make a stable cat look like a kidney case, which is why the urine sample matters as much as the blood. A meal within 6 hours raises BUN and turns the sample milky with fat; a stressful ride can push glucose to 200 to 300 mg/dL in a cat that is not diabetic. Outside the lab, lilies, 1 tablet of human painkiller, or 1 tube of dog flea product do kidney damage in hours, so check the toxin list before the plant comes home.

Five steps for this week

• Book a morning slot, fast 6 to 8 hours, and bring a fresh urine sample if the clinic accepts one.
• Ask for the actual numbers, not normal or abnormal, and send everything to the same lab as last time.
• Start the weight log today: 1 entry every 14 days, same scale, last 6 months in one place.
• Count urine clumps for 3 days, then count again after any change in food or water intake.
• Photograph the printed results with the date, so the next visit compares 2 real sheets instead of memory.

Six items, 2 rise lines, 4 home records, 180-day clock. The panel only pays off when the numbers are compared, and comparing is the owner's job. A weight trend chart is the cheapest early signal in the file, and when kidney values are the ones moving, ask about the electrolyte panel next.

Terms mentioned in this article

SDMAT4USGBUN

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