What lab values change with aging, and what does it mean?

Oct 24, 2025 5 min read •

senior care Healthy Aging Preventative Health

According to the National Institute on Aging, chronological aging is the single largest risk factor for most common chronic diseases. As we age, our body's physiology undergoes natural changes that are often reflected in routine blood work. Knowing what lab values change with aging can help distinguish between normal shifts and potential red flags for your health.

Quick Summary

With advancing age, normal laboratory ranges can shift for many biomarkers, including increased glucose, creatinine, and alkaline phosphatase, and decreased kidney function (eGFR), albumin, and various hormones. Discussing these expected physiological changes with a healthcare provider is essential for accurate interpretation and determining if abnormal values indicate disease or are just part of the aging process.

Key Points

Blood Cell Counts Adjust: The Complete Blood Count (CBC) in older adults often shows a slight decrease in red blood cells, white blood cells, and platelets, reflecting a reduced bone marrow reserve and immune system efficiency.
Kidney Function Declines: The Glomerular Filtration Rate (eGFR), a measure of kidney function, naturally declines with age. While serum creatinine may remain steady due to muscle mass loss, eGFR provides a more accurate picture of age-related renal changes.
Hormones Shift and Fluctuate: Aging alters hormone levels, including increased Thyroid Stimulating Hormone (TSH) and decreased sex hormones like testosterone. These changes can affect metabolism and vitality but are part of the normal aging process.
Inflammatory Markers Rise: Chronic, low-grade inflammation associated with aging can cause baseline Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) levels to be slightly higher in older adults.
Glucose Tolerance Worsens: Post-meal glucose levels and overall glucose tolerance tend to decrease with age, a factor linked to increased insulin resistance. Regular monitoring is crucial to distinguish normal changes from prediabetes or diabetes.
Cholesterol and Albumin Change: Total cholesterol and triglycerides often increase with age, while protective HDL cholesterol and key blood protein albumin tend to decrease. This can increase cardiovascular risk and indicate nutritional status.

Understanding Age-Related Changes in Blood Work

As people get older, interpreting routine blood tests can become complex. What is considered a 'normal' lab value for a 30-year-old may differ significantly for a 70-year-old. This distinction is crucial because misinterpreting these results can lead to unnecessary anxiety, over-investigation, or even the misdiagnosis of a health condition. A holistic view that considers age-specific physiological changes, lifestyle factors, and co-existing conditions is essential.

The Complete Blood Count (CBC) and Aging

The Complete Blood Count is one of the most common blood tests, providing information about red blood cells, white blood cells, and platelets. Many of these values show slight, normal declines in healthy older adults.

Red Blood Cells (RBC), Hemoglobin (Hgb), and Hematocrit (Hct): Healthy seniors may show a slight decrease in these markers. While anemia is more common with age, lower levels should not be automatically attributed to aging. They can indicate underlying issues like nutritional deficiencies (iron, B12), chronic disease, or gastrointestinal bleeding. Low levels should always be investigated further.
White Blood Cells (WBC): The total white blood cell count may be slightly lower in older adults. This reflects an aging immune system (immunosenescence). However, significant deviations still signal an infection or inflammatory process, though the elderly may not mount as robust of an inflammatory response.
Platelets (PLT): Similar to WBCs, platelet counts may show a slight, gradual decrease. Abnormally low levels should still be evaluated for conditions that affect bone marrow production or increase platelet destruction.

Kidney and Liver Function Panels

Renal and hepatic functions are known to change significantly over time.

Kidney Function (Creatinine and eGFR): With age, there is a natural decline in the glomerular filtration rate (GFR), which measures kidney function. While serum creatinine is a primary marker, a decrease in muscle mass in older adults can mask a drop in GFR, causing creatinine levels to appear deceptively normal. This is why estimated GFR (eGFR) calculations, which incorporate age, are vital for accurate assessment. Blood Urea Nitrogen (BUN), another kidney marker, often increases with age as kidney clearance slows.
Liver Function (Albumin and Enzymes): The liver's capacity and size can decrease with age, but routine liver enzyme tests (ALT, AST) often remain stable in healthy older individuals. A key change is a gradual decline in serum albumin, a protein produced by the liver. While healthy seniors can maintain normal albumin, lower levels are associated with frailty, malnutrition, and increased mortality risk in older patients.
Alkaline Phosphatase (ALP): This enzyme tends to increase with age, especially in women. Elevated levels that are within the age-adjusted range are often normal, but a significant elevation still warrants investigation for bone or liver issues.

Hormonal Changes and Inflammatory Markers

Several key hormones and inflammatory markers are affected by the aging process.

Thyroid Stimulating Hormone (TSH): As the thyroid gland ages, there is a natural reduction in its function. This can lead to a slight increase in baseline TSH levels, making the diagnosis of hypothyroidism in older adults more complex.
Glucose: The body's ability to regulate glucose can decline with age. Both fasting glucose and postprandial (after eating) glucose levels tend to increase. This is often due to age-related insulin resistance. Higher ranges are considered normal for healthy seniors, but a consistent pattern of high glucose may indicate evolving prediabetes or diabetes.
Lipids (Cholesterol and Triglycerides): Total cholesterol and triglycerides often increase with age. Conversely, protective high-density lipoprotein (HDL) cholesterol may decrease, particularly in postmenopausal women. This shift contributes to a higher cardiovascular risk profile in older adults.
Inflammatory Markers (ESR and CRP): Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) are general markers of inflammation. Both tend to show higher baseline levels in healthy older individuals. A moderately elevated CRP or ESR may be a normal feature of aging, but a significant or sustained increase could point to an infection, autoimmune disease, or other chronic inflammatory condition.

Comparison of Lab Value Shifts with Aging


Lab Value	Normal Shift with Aging	Medical Interpretation	Clinical Consideration
Creatinine/eGFR	Creatinine often stable; eGFR declines	GFR decreases due to fewer nephrons	Use eGFR, not just creatinine, to assess kidney function.
Albumin	Slight decrease	Associated with malnutrition, frailty	Investigate for dietary issues or chronic disease.
Alkaline Phosphatase	Slight increase	Often normal; can relate to bone turnover	Significant increase needs investigation (bone/liver).
TSH	Slight increase	Less efficient thyroid function	May still indicate hypothyroidism; compare to baseline.
Glucose	Fasting minimal change; postprandial increases	Reduced glucose tolerance; insulin resistance	Higher ranges normal, but monitor for diabetes.
ESR/CRP	Baseline levels slightly higher	Normal aging, subclinical inflammation	Significant rise indicates active infection/inflammation.
HDL Cholesterol	Decreases (especially women)	Contributes to increased cardiovascular risk	Manage diet, exercise, and discuss with a physician.
Testosterone (Free)	Decreases (men)	Normal hormonal decline	Can contribute to lower libido, muscle mass.

The Importance of Context and Dialogue

Understanding that lab values can change with aging is not an excuse to ignore potential health problems. Instead, it’s a call for a more nuanced and informed conversation with your healthcare provider. Medical professionals are trained to consider your full medical history, medications, lifestyle, and other physical symptoms alongside your blood work results.

For example, while a mildly elevated ESR might be a normal age-related finding, if it's accompanied by fatigue and joint pain, it becomes a crucial piece of the puzzle suggesting an inflammatory process like arthritis. Similarly, a slightly lower hemoglobin level might be a natural change, but a significant drop warrants a search for the root cause. For a deeper understanding of how health changes in later life, consider exploring resources like the National Institute on Aging.

Conclusion

Routine laboratory tests remain a cornerstone of preventative and diagnostic medicine for all ages. However, a 'one-size-fits-all' approach to interpreting these results is inadequate for older adults. By understanding the typical physiological shifts in lab values that occur with aging, both seniors and their healthcare teams can make more informed decisions. This allows for better health management, reduces unnecessary procedures, and provides a clearer path to distinguishing between normal aging and treatable illness. Empower yourself by being an active participant in your healthcare and always seeking personalized medical advice based on your complete health picture.

Frequently Asked Questions

Not all lab values change significantly. Some remain relatively stable in healthy older individuals, while others, like markers for kidney function (eGFR), glucose tolerance, hormones, and inflammation (ESR, CRP), can show notable shifts. A healthcare provider will interpret your results based on age-adjusted reference ranges.

Yes. Lab results are just one piece of the puzzle. An older adult might have blood work within normal age-adjusted ranges but still exhibit symptoms of a disease. A doctor will always combine lab findings with a physical exam, your symptoms, medical history, and other diagnostic tools to make a diagnosis.

Estimated Glomerular Filtration Rate (eGFR) is a calculation that takes into account your age, sex, and serum creatinine levels. As you get older, you tend to have less muscle mass, which can cause serum creatinine levels to appear misleadingly low or normal, even if kidney function is declining. The eGFR provides a more accurate assessment of your kidneys' filtering capacity.

With age, changes in metabolism can lead to increased insulin resistance, which can cause blood glucose levels to rise, particularly after meals. Similarly, hormonal shifts and metabolic changes can contribute to higher total cholesterol and triglyceride levels. These are common age-related trends that increase the risk for heart disease and diabetes.

Slightly higher baseline levels of inflammatory markers like Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) are often a normal part of aging, reflecting a low-grade inflammatory state. However, a significant or rapid increase, especially if accompanied by other symptoms like fever or unexplained pain, should be investigated further by your doctor.

The key is the context. A gradual change in a lab value over many years is more likely a normal aging effect. A rapid or significant change, especially alongside new or worsening symptoms like fatigue, weight loss, or pain, is more concerning. Open communication with your doctor, including a review of past test results, is the best approach.

Yes, many medications can alter blood test results. It is crucial to provide your doctor with a complete list of all prescriptions, over-the-counter drugs, and supplements you are taking. For example, diuretics can affect potassium levels, and corticosteroids can influence white blood cell counts.

References

Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider regarding personal health decisions.