Blood tests for older adults
For people aged 65 or older and the family members who help keep track of their results, such as adult children and partners.
11 tests explainedAI-verified against cited sources. Awaiting expert reviewLast reviewed 2026-10-19
With age, more medicines and often more clinics come into the picture, and a few results mean something a little different. Creatinine-based kidney numbers depend on muscle, TSH tends to drift higher, and diabetes goals are set person by person. Some common medicines can shift sodium, potassium or B12, so these tests often come up when a medicine starts or changes, or after years on one.
The tests that matter most
Most important first. Each one links to its full page, where the note for this group sits near the top.
eGFR (Creatinine-based)
eGFR estimates how well the kidneys filter, and it guides the dose of many medicines the kidneys clear. KDIGO notes that in older adults with low muscle mass, creatinine-based eGFR can overestimate kidney function, which can lead to doses that are too high.
- Usual adult range
- 60 and above mL/min/1.73 m²
Creatinine
Creatinine comes from muscle, so it runs lower when muscle mass is low. KDIGO says creatinine in older adults should be read with body build in mind, since muscle loss is common and can make a creatinine-based eGFR look better than kidney function really is.
- Men, 15+
- 0.74–1.35 mg/dL
- Women, 16+
- 0.59–1.04 mg/dL
eGFR (Creatinine + Cystatin C, CKD-EPI 2021)
Cystatin C is a second kidney marker that is less tied to muscle than creatinine. KDIGO recommends an eGFR that combines both when the creatinine-based number is less accurate and the result affects decisions, such as a medicine dose.
- Usual adult range
- 60 and above mL/min/1.73 m²
Sodium
The American Geriatrics Society notes that some antidepressants, some seizure medicines, antipsychotics, diuretics and tramadol can lower sodium. It suggests checking sodium closely in older adults when these are started or the dose changes.
- Usual adult range
- 135–145 mmol/L
Potassium
The American Geriatrics Society notes that some medicine combinations raise the chance of high potassium when kidney function is reduced. Examples are two blood pressure medicines that act on the renin-angiotensin system (such as ACE inhibitors or ARBs), one of these with a potassium-sparing diuretic, or the antibiotic trimethoprim-sulfamethoxazole with an ACE inhibitor, ARB or ARNI.
- Usual adult range
- 3.5–5.2 mmol/L
Hemoglobin
Anemia is common in older adults. About a third of cases come from low iron, B12 or folate, about a third from inflammation or kidney disease, and about a third have no clear cause. Even a drop in hemoglobin that stays above the anemia cutoff has been linked to health problems at older ages.
Source: Blood (2024)
- Men, 16+
- 13–17.7 g/dL
- Women, 16+
- 11.1–15.9 g/dL
Vitamin B12 (Cobalamin)
Older age, metformin and acid-reducing medicines called proton pump inhibitors are all linked to low B12. The ADA suggests checking B12 every year in older adults who have taken metformin for more than 4 years.
Sources: American Family Physician (2025) and American Diabetes Association (2026)
- Usual adult range
- 232–1,245 pg/mL
Methylmalonic Acid (MMA), Serum
When a B12 result is borderline, a 2025 American Family Physician review suggests an MMA test as the next step, to help show whether the body is short of B12.
Source: American Family Physician (2025)
- 60–79
- 69–390 nmol/L
- 80+
- 85–423 nmol/L
Hemoglobin A1c (HbA1c)
For older adults, the ADA suggests A1c goals set person by person. Lower goals fit people in good health, less strict goals fit those with frailty or complex health, and avoiding low blood sugar comes first. For people in very poor health, it suggests not relying on A1c.
- Usual adult range
- 4.8–5.6 %
TSH (Thyroid Stimulating Hormone)
TSH tends to drift a little higher with age. The ETA suggests considering age-specific TSH ranges for older people, so a result slightly above the usual adult range can be common at older ages.
- Usual adult range
- 0.45–4.5 mIU/L
Vitamin D (25-Hydroxy)
Vitamin D tests are often ordered, but the Endocrine Society suggests against routine vitamin D testing in the general population, including adults 75 and older. Your clinician may still check it for a specific reason.
Source: Endocrine Society (2024)
- Usual adult range
- 30–100 ng/mL
Ranges shown are the usual adult ranges labs print. The range on your own report is the one your result is judged against.
Getting results you can compare
- When results come from several clinics, keep them together and compare like with like. MedlinePlus notes that labs often use different methods and ranges, so results from different labs can't be compared directly.
Source: MedlinePlus
- Medicine changes and blood tests often go together. The American Geriatrics Society suggests checking sodium closely when certain medicines start or change, and the ADA suggests eGFR every 3 to 6 months for people on metformin who are at risk of kidney decline.
Sources: American Geriatrics Society (2023) and American Diabetes Association (2026)
- A single raised TSH is often rechecked. The ETA suggests repeating TSH and free T4, along with TPO antibodies, preferably after 2 to 3 months, because TSH can rise for a while for many reasons, such as a recent illness.
Good to know
- Usual ranges are not always built around older adults. The ETA considers a mildly raised TSH of 4.0 to 7.0 mIU/L in people over 80 a normal adaptation to aging.
- The ADA notes that A1c can be inaccurate after a blood transfusion and with conditions that change red blood cell turnover, which in older adults include kidney failure and recent major blood loss. In those cases, it suggests using glucose monitoring to set goals.
- MedlinePlus notes that it's common for healthy people to sometimes have a result outside the usual range, and that clinicians look at other information about your health to understand it.
Source: MedlinePlus
Questions you could ask
- Is my kidney function estimate accurate for my muscle mass, or would cystatin C help?
- Do any of my medicines call for regular sodium or potassium checks?
- What A1c goal fits my health right now?
- Is my TSH in the usual range for my age?
- Given the medicines I take, is it time to check my B12?
Sources
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease, Kidney Disease: Improving Global Outcomes (2024)
- American Geriatrics Society 2023 updated AGS Beers Criteria for potentially inappropriate medication use in older adults, American Geriatrics Society (2023)
- How I treat anemia in older adults, Blood (2024)
- Vitamin B12 Deficiency: Common Questions and Answers, American Family Physician (2025)
- 13. Older Adults: Standards of Care in Diabetes-2026, American Diabetes Association (2026)
- 2013 ETA Guideline: Management of Subclinical Hypothyroidism, European Thyroid Association (2013)
- Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline, Endocrine Society (2024)
- How to Understand Your Lab Results, MedlinePlus
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-19. How we build and check these pages.
Educational information, not medical advice. Blood Test Tracker doesn’t diagnose or treat, and it doesn’t replace your clinician. Talk with your clinician before changing medications, supplements or care.