How Often Should Senior Dogs Get Bloodwork?

Direct answer: every 6–12 months is a reasonable guideline range for routine senior-dog laboratory screening, but it is not a rule that every older dog needs the same panel twice a year. The 2023 AAHA Senior Care Guidelines recommend a comprehensive CBC, chemistry panel, and urinalysis every 6–12 months for senior dogs. The right interval can be shorter or different when a dog has symptoms, takes certain medications, has a diagnosed condition, or has a previous abnormal result. AAHA diagnostic table

The important nuance is that the evidence supports regular senior health screening more strongly than it supports one universal blood-test schedule. Prospective dog studies show that screening can uncover problems owners did not know were present, but they have not shown that testing every six months rather than every twelve months makes healthy senior dogs live longer. Marynissen et al., 2025

Evidence confidence: Moderate overall.

Confidence is high that AAHA currently recommends CBC, chemistry, and urinalysis every 6–12 months for senior dogs. Confidence is moderate that repeated screening provides useful early-detection and longitudinal information. Confidence is low that one fixed testing frequency improves lifespan or healthspan for every otherwise healthy senior dog, because randomized comparisons of screening schedules are lacking.

First, what counts as a senior dog?

There is no single birthday at which every dog becomes senior.

AAHA defines the senior life stage in dogs as roughly the last 25% of expected lifespan, rather than using one age for every breed and body size. A giant breed may enter that stage years before a small dog. AAHA, Defining the Senior Patient

That matters because a statement such as “start senior bloodwork at age seven” is convenient but too broad. Age, expected lifespan, health history, breed-related risk, medications, previous results, and what has changed at home all affect how useful a particular test is.

What does the 6–12 month recommendation actually include?

AAHA’s 2023 senior-care table gives the following routine frequencies for senior dogs:

AAHA diagnostic table

AAHA also describes a broader senior medical workup once or twice a year and emphasizes the history and physical examination alongside laboratory testing. The guideline itself states that its recommendations are guidance rather than an exclusive protocol and that individual needs and resources can justify variation. AAHA, Evaluating the Healthy Senior Pet

So “every six months” should not be interpreted as “repeat every available biomarker every six months.” It is a framework for discussing what should be repeated for this dog.

What do screening studies in older dogs actually find?

The case for screening is not only theoretical.

In a prospective 2017 study, researchers evaluated 100 client-owned senior and geriatric dogs whose owners considered them healthy. The screening included a physical examination, CBC, serum chemistry, urinalysis, blood pressure, and other assessments. Physical and laboratory abnormalities were common. The authors also stressed an important limitation: many blood abnormalities were mild and required follow-up before their clinical importance could be determined. Willems et al., 2017

A larger 2025 prospective study started with 122 apparently healthy older dogs. After the baseline workup, 24 dogs, or 20%, were diagnosed with at least one disease under the study’s criteria. The 98 dogs considered healthy at baseline then received history, physical examination, blood testing, and urinalysis every 12 months for two years. During follow-up, new diagnoses included neoplasia, chronic kidney disease, neurologic disease, and orthopedic disease. Marynissen et al., 2025

That supports the value of checking apparently healthy older dogs rather than waiting for obvious illness.

But the same study gives a useful warning against turning “screening helps” into “more blood tests must always be better.” The authors concluded that repeated screening for kidney disease and careful physical, neurologic, and orthopedic assessment appeared particularly relevant. They found limited added value from repeatedly measuring many CBC, liver-enzyme, and electrolyte variables in otherwise healthy-appearing older dogs. They also explicitly noted that their study did not prove screening improves overall outcomes, which would require comparing screened dogs with dogs managed under another strategy. Marynissen et al., 2025

Why urinalysis belongs in the conversation

Owners often use “bloodwork” as shorthand for the entire senior lab check, but urine can add information that a blood panel does not.

In the 2025 longitudinal study, renal screening included urine concentration and protein assessment as well as blood markers. The authors specifically supported urinalysis in aging-dog screening and noted that it is often neglected in practice. Marynissen et al., 2025

That does not mean every unusual urine result is disease. It means that a “normal blood panel” is not necessarily a complete kidney or urinary-health screen.

Bloodwork is only one part of senior screening

Some important problems are found with hands, eyes, ears, history, and observation rather than a laboratory analyzer.

In the 2025 cohort, physical examination contributed substantially to the detection of malignant tumors; the study also found orthopedic and neurologic problems during follow-up. AAHA similarly emphasizes changes in appetite, thirst, movement, play, elimination, behavior, hearing, and vision, together with a thorough physical examination. Marynissen et al., 2025 AAHA

This is why a senior visit should not become “drop off blood and wait for the green check marks.” A new lump, muscle loss, difficulty rising, increased thirst, appetite change, or altered behavior can matter even when routine laboratory values remain within their reference intervals.

Is a trend more useful than a single result?

Often it can be, but trends also need interpretation.

A small 2012 study repeatedly measured routine serum chemistry analytes in 11 healthy dogs and found substantial individuality for many measures. The authors concluded that population reference intervals can sometimes miss biologically meaningful within-dog change. Ruaux et al., 2012

A later study sampled 13 healthy dogs weekly for eight weeks and quantified normal within-dog variation in serum and urine analytes. The size of that normal variation differed markedly by analyte. Selin et al., 2023

The useful lesson is not that every movement from a dog’s old number is meaningful. It is that direction, magnitude, repeatability, laboratory method, hydration, fasting status, medications, symptoms, and the dog’s prior pattern all matter. A trend can add context; it cannot diagnose a disease by itself.

When might the schedule be different?

A healthy-dog screening interval should not be reused as a monitoring plan for a dog with a medical problem.

A veterinarian may reasonably choose a different interval when a dog has:

• a previously abnormal or changing laboratory result;
• a diagnosed kidney, liver, endocrine, hematologic, or other condition;
• a medication that requires laboratory monitoring;
• a substantial change in weight, appetite, thirst, urination, energy, mobility, or behavior; or
• another clinical finding that needs follow-up.

Those situations are no longer simply “routine senior screening.” The frequency and tests should be selected around the condition and the decision the result is meant to inform.

Nara’s interpretation

For an otherwise healthy senior dog, 6–12 months is a defensible planning range for discussing CBC, chemistry, and urinalysis with the veterinary team because that is the current AAHA recommendation. Nara would not turn that range into a universal rule that more frequent testing is always superior.

The stronger practical idea is to build a usable longitudinal record:

1. know when and why the test was performed;
2. keep the actual result, units, and laboratory reference range;
3. record relevant context such as medications, supplements, fasting status, weight, body condition, symptoms, and recent changes;
4. compare new results with prior results without treating every fluctuation as disease; and
5. use the veterinary interpretation and the dog’s clinical picture to decide what needs confirmation or follow-up.

Nara brings laboratory results into the same longitudinal record as nutrition, body condition, movement, medications, and owner observations. The goal is not to generate more tests. It is to make the tests that are done easier to interpret in context over time. About Nara

What this evidence does not tell us

We do not have a randomized canine trial showing that routine bloodwork every six months produces better survival or quality of life than annual screening in otherwise healthy senior dogs.

Screening also creates follow-up work. Mild or borderline abnormalities can be transient, age-related, analytically variable, or clinically important. The result may need repetition, urine testing, imaging, examination, or no immediate intervention at all. The 2017 and 2025 screening studies are useful because they show both sides: unrecognized disease can be found, and abnormal numbers do not automatically equal consequential disease. Willems et al., 2017 Marynissen et al., 2025

That is why the best question is not simply “Is my senior dog due for bloodwork?” It is “What are we screening for, what else should be checked, and what would we do differently if something changes?”

Sources

1. American Animal Hospital Association. Diagnostic Tests and Recommended Frequencies for Senior Dogs and Cats. 2023. https://24051120.fs1.hubspotusercontent-na1.net/hubfs/24051120/Guidelines%20PDFs/Senior%20Care/table-1-diagnostic-tests-and-recommended-frequencies-for-senior-dogs-and-cats.pdf
2. American Animal Hospital Association. Evaluating the Healthy Senior Pet. 2023 AAHA Senior Care Guidelines for Dogs and Cats. Published December 13, 2022. https://www.aaha.org/resources/2023-aaha-senior-care-guidelines-for-dogs-and-cats/evaluating-the-healthy-senior-pet/
3. American Animal Hospital Association. Defining the Senior Patient. 2023 AAHA Senior Care Guidelines for Dogs and Cats. Published December 13, 2022. https://www.aaha.org/resources/2023-aaha-senior-care-guidelines-for-dogs-and-cats/defining-the-senior-patient/
4. Marynissen S, Mortier F, Duchateau L, Smets P, Daminet S, Paepe D. Exploring the Importance of Repeated Health Screening in Healthy Older Dogs. Journal of Veterinary Internal Medicine. 2025;39(4):e70166. https://doi.org/10.1111/jvim.70166
5. Willems A, Paepe D, Marynissen S, et al. Results of Screening of Apparently Healthy Senior and Geriatric Dogs. Journal of Veterinary Internal Medicine. 2017;31(1):81-92. https://doi.org/10.1111/jvim.14587
6. Ruaux CG, Carney PC, Suchodolski JS, Steiner JM. Estimates of biological variation in routinely measured biochemical analytes in clinically healthy dogs. Veterinary Clinical Pathology. 2012;41(4):541-547. https://doi.org/10.1111/j.1939-165X.2012.00473.x
7. Selin H, Pelander L, Hagman R, Häggström J, Ström Holst B. Biological variation of biochemical urine and serum analytes in healthy dogs. Veterinary Clinical Pathology. 2023;52(2):232-245. https://doi.org/10.1111/vcp.13225

Related questions

• What should be included in a senior dog blood panel?
• When is a dog considered senior?
• Why can urinalysis matter even when bloodwork looks normal?
• Which changes in a senior dog should prompt testing sooner?
• How should repeated creatinine, liver-enzyme, or blood-cell results be compared over time?
• Does more frequent screening help dogs live longer?