Senior Cat Blood Test Results: Common Terms Explained in Plain English

Senior cat blood test results can look confusing when a report contains abbreviations, numbers, arrows and terms such as “high”, “low”, “borderline” or “monitor”.

This guide explains the common language owners may see on a report. It cannot show what an individual result means for your cat because your vet will consider the full pattern alongside your cat’s health, examination, weight, urine results and previous tests.

Disclaimer: This article is for educational purposes only and is not a substitute for professional veterinary advice. Discuss blood test results with the vet who ordered them and do not use online reference ranges to diagnose your cat or change their food, medication or supplements.

Quick answer: senior cat blood test results

A senior cat blood report may include blood-cell counts, kidney and liver values, thyroid hormone, glucose, proteins and electrolytes. It may also flag results as high, low, borderline or outside a reference range.

A flagged result does not automatically mean that your cat is ill or show what caused the change. Ask your vet which results matter most, how they compare with previous tests and whether any follow-up is recommended.

Common sections on a senior cat blood test report

Blood reports vary by clinic and laboratory, but many include two broad areas:

Section	What it usually covers	Plain-English purpose
CBC	Red blood cells, white blood cells and platelets	Gives your vet a broad picture of the blood cells
Chemistry panel	Organ-related values, proteins, minerals and other markers	Helps your vet look for patterns across several body systems
Thyroid test	T4 or related thyroid values	Assesses thyroid hormone in the context of your cat’s signs and other results
Glucose	Blood sugar	Considered alongside stress, symptoms and sometimes urine results
Electrolytes	Sodium, potassium and chloride	Helps your vet assess hydration and body balance
Reference range	The laboratory’s comparison interval	Shows the range against which that laboratory flags the result
Flagged result	A value marked high, low or outside the range	Draws attention to a number but does not explain its meaning by itself

Some cats may also have urine testing, blood pressure checks, or other tests depending on their age, symptoms, and previous results.

Why vets often recommend blood tests for senior cats

Blood tests can help your vet assess broad areas of internal health, including:

• blood cells
• kidney-related values
• liver-related values
• thyroid hormone
• blood sugar
• proteins
• electrolytes

Results can also provide a baseline for comparison with later tests. A pattern across several reports may give your vet more useful context than one result viewed on its own.

For more background on routine senior care, you may also find Senior cat check-ups: what “senior wellness” visits often include helpful.

Why one result rarely tells the whole story

A value outside the laboratory’s reference range is one piece of information. It does not automatically show the cause or how significant the result is for your cat.

Results may be considered alongside:

• hydration
• stress during the appointment
• recent eating
• medication
• sample quality
• the laboratory’s reference range
• examination findings
• urine results
• blood pressure
• weight changes
• previous blood tests

Your vet may recommend monitoring, another type of test or a repeat blood test when more context is needed.

Blood cell terms: CBC, red cells, white cells, and platelets

CBC

CBC means complete blood count. It measures different types of blood cells and gives your vet a broad picture of the blood.

Red blood cells

Red blood cells carry oxygen around the body. Your vet may consider these values alongside your cat’s energy, gum colour, breathing, appetite and other results.

White blood cells

White blood cells are connected with the immune system. Changes may be considered alongside signs of inflammation, infection, stress and your cat’s examination findings.

Platelets

Platelets help blood clot. Platelet results may sometimes need careful interpretation because the way a sample behaves can affect the reading.

None of these values should be interpreted alone. Your vet will look at the blood-cell pattern and your cat’s wider health.

Kidney-related terms: creatinine, urea/BUN, SDMA, and phosphorus

Kidney-related results are commonly discussed in senior cats, but they need careful interpretation. Your vet will usually look at the pattern rather than one isolated value.

For more detail on early owner observations, see Senior cat kidney disease: early signs owners might notice.

Creatinine

Creatinine is a waste product that vets often consider when assessing kidney function.

It is usually interpreted with other information, such as:

• Hydration
• Urine concentration
• Body condition
• Weight changes
• Other kidney-related values
• Previous results

Creatinine is one part of a wider kidney assessment and does not provide a diagnosis by itself.

Urea or BUN

Urea, sometimes shown as BUN depending on the report, is another waste-product term your vet may discuss.

It can be linked with kidney assessment, but it can also be influenced by other factors. That is why your vet usually interprets it alongside creatinine, urine findings, hydration, and your cat’s general condition.

SDMA

SDMA is a kidney-related marker included on some blood panels.

Your vet may use it as part of a wider kidney assessment, especially when looking for patterns or changes over time. It still needs context and may be interpreted alongside urine testing, creatinine, body weight, and symptoms.

Phosphorus

Phosphorus is a mineral that may be discussed when vets are looking at kidney health or overall body balance.

It should not be interpreted alone, and owners should not change diet or add supplements based only on a phosphorus value. If your vet mentions phosphorus, ask how it fits with your cat’s other results and overall health.

Liver-related terms: ALT, ALP, and bilirubin

Liver-related values can appear on a chemistry panel. These results can look worrying on a report, but they still need the full veterinary picture.

ALT

ALT is a liver enzyme. Your vet may compare it with other liver-related values, appetite, weight, medication history and examination findings.

ALP

ALP is another enzyme that may appear on a chemistry report. It is usually considered alongside ALT, bilirubin and the rest of the blood-test pattern.

Bilirubin

Bilirubin is a pigment-related value. Your vet may consider it in the context of the liver, bile system, red blood cells and other test results.

These terms identify areas your vet may want to assess. They do not explain the cause of a result by themselves.

Thyroid term: T4

T4 is a thyroid hormone commonly measured in older cats. Your vet may consider the result alongside your cat’s weight, appetite, behaviour, examination findings and other test results.

A T4 result may be clearly within range, raised, borderline or need further context. It should not be interpreted on its own at home.

For a fuller explanation of T4, free T4, borderline results and repeat testing, see our Senior Cat Thyroid Blood Tests guide.

If you are mainly trying to understand the signs owners may notice at home, see Hyperthyroidism in Older Cats.

Glucose and blood sugar

Glucose means blood sugar.

Stress during a veterinary appointment can affect glucose readings in some cats. Your vet may compare the result with appetite, thirst, weight, behaviour, urine findings and any further tests.

Ask whether the glucose result fits with what you have noticed at home and whether any follow-up is needed.

Proteins and electrolytes

Total protein, albumin, and globulin

A report may include total protein, albumin and globulin. Your vet considers the pattern because protein values can relate to several areas, including hydration, inflammation and organ function.

Sodium, potassium, and chloride

Sodium, potassium and chloride are electrolytes involved in normal body function. Your vet may interpret them alongside hydration, kidney-related values, appetite, vomiting, diarrhoea and your cat’s general condition.

Ask whether an abnormal result is mild, significant, stable or something your vet wants to recheck.

What “high”, “low”, “borderline”, or “monitor” may mean

Reports often use short labels or automatically flag values. These terms describe the report, but they do not diagnose a condition.

Term on the report	Plain-English meaning	A useful question for your vet
Reference range	The comparison interval used by that laboratory	“Is my cat’s result meaningfully outside this range?”
Flagged	Automatically marked for attention	“Does this flag matter when you look at the full pattern?”
High	Above the laboratory’s reference range	“Is this mildly or significantly raised?”
Low	Below the laboratory’s reference range	“Does this fit with my cat’s health or other results?”
Borderline	Near the edge of the range or not clearly normal or abnormal	“Would you recommend monitoring or repeating it?”
Monitor	Watch the value or the cat over time	“What should I note at home?”
Stable	Similar to previous results	“Is this reassuring in my cat’s case?”
Trending	Changing across more than one test	“Is the trend more important than today’s number?”
Recheck	Repeat the test for comparison	“When should it be repeated, and what are you looking for?”

Reference ranges can vary between labs, and some cats have individual patterns that your vet will recognise over time.

The safest question is not “What does this number mean online?” but:

“What does this result mean for my cat, based on the full picture?”

Questions to ask your vet about senior cat blood test results

You do not need to understand every abbreviation. Ask your vet to identify the results that matter most and explain what they mean in the context of your cat.

Useful questions include:

• Which results are most important?
• Are any values only mildly outside the reference range?
• Do the results fit with my cat’s health or behaviour?
• How do they compare with previous tests?
• Is there a pattern across several values?
• Would urine testing, blood pressure or repeat bloodwork add useful context?
• What should I monitor at home?
• When should we follow up?
• Which changes should prompt me to contact you sooner?

Owner-friendly blood test discussion checklist

Before the appointment, it can help to have three things ready:

• any recent blood or urine reports
• a few notes about changes in weight, appetite, drinking, litter tray habits or behaviour
• the questions you most want your vet to answer

The aim is not to interpret the results yourself. It is simply to give your vet useful context and make the discussion easier.

What to keep at home after the appointment

Keep copies of:

• blood test reports
• urine results, when provided
• weight records
• veterinary medication instructions
• follow-up dates
• brief notes from the appointment

Keeping reports together makes it easier for your vet to compare results over time.

When to speak to your vet sooner

Do not wait for a routine follow-up if your senior cat becomes noticeably unwell after testing or while you are monitoring a result.

Contact your vet sooner if there is a marked change such as not eating, repeated vomiting, weakness or collapse, breathing difficulty, obvious pain, difficulty urinating, or a sudden major behaviour change.

Also contact your vet if they have specifically asked you to watch a particular result or symptom and that change occurs. A blood report should never be considered in isolation when your cat appears unwell.

Final thoughts

Senior cat blood test results can look intimidating, especially when the report is full of abbreviations and flagged values. But you do not need to decode every number by yourself.

Your vet’s role is to interpret the full pattern. Your role is to ask clear questions, share what you have noticed at home, and follow the plan your vet recommends.

For a broader overview of health changes and routine care in older cats, see our Senior Cat Health guide.

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FAQs

External references

• Cornell Feline Health Center: The Special Needs of the Senior Cat
• AAHA: The ABCs of Cat Bloodwork: What Those Results Really Mean