Which Laboratory Tests Should You Consider at Different Stages of Life?

The laboratory tests that make sense for you at age 25 may not be the same tests that deserve attention at age 45, 65, or during pregnancy.

Age influences your risk for certain health conditions, but it is only one part of the decision.

Your medical history, family history, medications, symptoms, lifestyle, previous laboratory results, pregnancy status, and individual health goals may all influence which tests are appropriate and how often they should be repeated.

That is why there is no single laboratory panel that every person needs at every age.

Instead, thoughtful laboratory testing should answer a useful clinical question: What information would help us understand your health, identify an important risk, investigate a symptom, or make a better medical decision?

If you are new to blood testing, start with our Patient’s Guide to Understanding Blood Work and Laboratory Testing or visit the Routine Laboratory Testing Resource Center.

Why Laboratory Testing Changes Throughout Life

Your health risks do not remain static.

During childhood and adolescence, testing may focus on inherited conditions, growth and development, or selected cardiovascular and metabolic risks.

During young adulthood, establishing useful baselines and identifying preventable risk factors becomes more important.

By middle age, blood sugar, cholesterol, cardiovascular risk, and the effects of medications or chronic conditions often deserve greater attention.

Later in life, laboratory monitoring may increasingly focus on kidney function, medication safety, nutritional status, anemia, diabetes, cardiovascular disease, and other age-associated health concerns.

The important point is that more testing is not necessarily better testing.

Some blood tests have well-established roles in preventive medicine, while others are most useful only when symptoms, medical history, medications, or specific risk factors justify ordering them.

Childhood and Adolescence: Establishing Healthy Foundations

Most routine laboratory testing during childhood should be coordinated with a pediatric healthcare professional because recommendations vary with growth, development, family history, and individual medical circumstances.

One increasingly important area is cholesterol screening.

The 2026 ACC/AHA dyslipidemia guideline recommends universal lipid screening between 9 and 11 years of age to help identify inherited lipid disorders such as familial hypercholesterolemia. Earlier testing may also be appropriate when a child has a strong family history of premature cardiovascular disease or severe cholesterol abnormalities.

Other laboratory testing in children and adolescents is typically more individualized.

Testing may be considered when there are concerns such as:

• Unexplained fatigue

• Abnormal growth or weight changes

• Heavy menstrual bleeding

• Symptoms of anemia

• Dietary deficiencies

• Obesity or metabolic risk

• Chronic medical conditions

• Medication monitoring

• A strong family history of certain diseases

A child generally does not need a large adult-style laboratory panel simply because a yearly physical is being performed.

Young Adulthood: Ages 18 to 34

Young adulthood is a useful time to establish a health baseline and make sure important preventive screenings have not been overlooked.

Many adults in their 20s feel completely healthy, but that does not mean preventive healthcare should be ignored.

Cholesterol and Cardiovascular Risk

A lipid panel measures values such as:

• Total cholesterol

• LDL cholesterol

• HDL cholesterol

• Triglycerides

These measurements help evaluate long-term cardiovascular risk and may identify inherited cholesterol disorders that otherwise produce no symptoms.

You can learn more about these measurements in Cholesterol and Lipid Testing Explained.

One important change in cardiovascular prevention occurred in 2026.

The updated ACC/AHA dyslipidemia guideline recommends that lipoprotein(a), or Lp(a), be measured at least once during adulthood. Lp(a) is largely genetically determined and may identify cardiovascular risk that is not apparent from a standard cholesterol panel.

Because Lp(a) is generally stable throughout life, it usually does not need to be checked repeatedly unless there is a specific reason.

Hepatitis B Screening

The CDC recommends that adults age 18 and older be screened for hepatitis B at least once during their lifetime using a three-test panel consisting of:

• Hepatitis B surface antigen

• Hepatitis B surface antibody

• Hepatitis B core antibody

Additional testing may be appropriate for people with ongoing risk factors.

Hepatitis C Screening

Hepatitis C can remain asymptomatic for many years.

The U.S. Preventive Services Task Force recommends hepatitis C screening for adults ages 18 through 79, while the CDC recommends at least one-time screening for adults age 18 and older. People with ongoing exposures or risk factors may require repeat testing.

HIV and Other Sexually Transmitted Infection Screening

The USPSTF recommends HIV screening for adolescents and adults ages 15 through 65, with testing outside that range when increased risk is present.

Testing for infections such as chlamydia, gonorrhea, and syphilis depends more on sexual history, pregnancy, anatomy, exposure, and individual risk than simply on age.

What About a CBC or CMP?

A complete blood count, or CBC, evaluates red blood cells, white blood cells, hemoglobin, hematocrit, and platelets.

A comprehensive metabolic panel, or CMP, provides information about glucose, electrolytes, kidney-related markers, liver-related measurements, calcium, and proteins.

Both are commonly ordered tests, but neither is a mandatory annual screening test for every healthy young adult.

They may be particularly useful when evaluating symptoms, monitoring medications, following previous abnormalities, or assessing an existing medical condition.

Ages 35 to 49: Metabolic Risk Becomes Increasingly Important

As adults enter their mid-30s and 40s, preventive laboratory testing increasingly focuses on metabolic and cardiovascular health.

This is an important period for identifying risk factors that may develop quietly for years before causing obvious symptoms.

Blood Sugar and Diabetes Screening

Blood sugar evaluation may include:

• Fasting glucose

• Hemoglobin A1C

• Oral glucose tolerance testing in selected situations

The USPSTF recommends screening for prediabetes and type 2 diabetes in asymptomatic adults ages 35 through 70 who have overweight or obesity. Earlier screening may be considered when additional risk factors are present.

You can read more about the differences between these measurements in Blood Sugar Testing Explained: Fasting Glucose, A1C, and Diabetes Risk.

This is particularly important because abnormal glucose regulation can develop gradually.

Finding prediabetes provides an opportunity to address nutrition, physical activity, weight, sleep, and other modifiable factors before diabetes develops.

Cholesterol and Cardiovascular Risk

Lipid testing also becomes increasingly important as cardiovascular risk accumulates.

Your physician does not interpret cholesterol in isolation.

The meaning of your LDL and other lipid measurements may depend on factors including:

• Age

• Blood pressure

• Diabetes

• Smoking

• Kidney disease

• Family history

• Previous cardiovascular disease

• Lp(a)

• Other cardiovascular risk factors

A single cholesterol value therefore does not tell the entire story.

Kidney and Liver Function

Kidney and liver measurements may be included in a metabolic panel when clinically appropriate.

These tests become particularly useful for people who:

• Have diabetes

• Have high blood pressure

• Have known kidney or liver disease

• Take medications requiring monitoring

• Have abnormal previous results

• Have symptoms suggesting an organ-function abnormality

For patients with diabetes, kidney-specific monitoring may also include urine albumin testing in addition to blood measurements such as creatinine and estimated glomerular filtration rate.

Menstruation, Iron Status, and Reproductive Health

Age alone should not determine whether iron testing is performed.

However, iron deficiency becomes particularly important to consider in people who menstruate, especially when bleeding is heavy or prolonged.

Possible laboratory evaluation may include:

• CBC

• Ferritin

• Serum iron

• Total iron-binding capacity

• Transferrin saturation

Symptoms such as fatigue, reduced exercise tolerance, dizziness, weakness, headaches, or restless legs may sometimes prompt evaluation for iron deficiency or anemia.

A CBC can suggest anemia, but it does not directly measure iron stores.

This is an example of why additional laboratory testing should usually be selected to answer a specific clinical question rather than automatically ordering every available test.

Pregnancy: Laboratory Testing Changes Significantly

Pregnancy is one of the clearest examples of a life stage in which laboratory testing changes substantially.

Prenatal laboratory testing may include assessments that are not routinely necessary outside pregnancy.

Depending on the stage of pregnancy and previous testing, evaluation commonly includes areas such as:

• Blood type and Rh status

• Complete blood count

• HIV screening

• Hepatitis B screening

• Hepatitis C screening

• Syphilis screening

• Other infectious disease testing when appropriate

• Genetic or carrier screening when appropriate

• Glucose testing for gestational diabetes

CDC guidance recommends HIV testing as early as possible during each pregnancy and screening for hepatitis B, hepatitis C, and syphilis during pregnancy.

Gestational diabetes screening generally takes place at or after 24 weeks, commonly between 24 and 28 weeks of pregnancy.

Pregnancy also changes normal laboratory physiology, meaning that certain blood-test reference ranges may differ from those used in nonpregnant adults.

For that reason, pregnancy laboratory results should always be interpreted in the appropriate clinical context.

Ages 50 to 64: Monitoring Long-Term Health Risks

By the 50s and early 60s, many adults have accumulated decades of exposure to cardiovascular, metabolic, environmental, and lifestyle risk factors.

Laboratory testing during this stage may increasingly emphasize long-term disease prevention and monitoring.

Depending on the individual, testing may include consideration of:

• Lipid panel

• Blood glucose or A1C

• Kidney function

• Liver-related measurements

• Electrolytes

• CBC

• Urine protein or albumin testing when indicated

Testing may also become more frequent for people who develop hypertension, diabetes, high cholesterol, kidney disease, cardiovascular disease, or other chronic conditions.

Medication use also matters.

Some medications require periodic monitoring of:

• Kidney function

• Liver measurements

• Electrolytes

• Blood-cell counts

• Thyroid function

• Drug-specific laboratory markers

At this stage of life, comparing current results with previous measurements can become especially valuable.

A gradual change over five or ten years may sometimes provide information that is not obvious when looking only at whether today's number falls inside a laboratory reference range.

That is why understanding how laboratory reference ranges should be interpreted is so important.

Age 65 and Beyond: Individualization Becomes Even More Important

Older adults often have more medical conditions, take more medications, and have greater variation in overall health than younger populations.

That makes individualized testing more—not less—important.

There is no single laboratory panel that every person over age 65 should automatically receive at fixed intervals.

Depending on health history, common areas of laboratory monitoring may include:

• Kidney function

• Electrolytes

• Blood sugar

• A1C

• Cholesterol

• Liver-related measurements

• CBC

• Nutritional markers when clinically appropriate

• Thyroid testing when indicated

Kidney function deserves particular attention in many older adults because kidney function may change with age and can affect how certain medications are dosed.

Similarly, anemia becomes more common with increasing age, but an abnormal hemoglobin should not simply be attributed to aging. The underlying cause may require evaluation.

The goal should remain the same: order tests that have a reasonable chance of changing medical decisions or improving care.

Should Everyone Have Thyroid Testing?

Not necessarily.

Thyroid testing usually begins with thyroid-stimulating hormone, or TSH, and may be followed by additional tests when appropriate.

Testing may be useful when symptoms or risk factors suggest thyroid disease, including situations involving unexplained changes in:

• Weight

• Energy

• Heart rate

• Temperature tolerance

• Bowel habits

• Menstrual patterns

Certain medications, previous thyroid disease, pregnancy-related circumstances, or abnormal examination findings may also justify testing.

However, the USPSTF currently concludes that evidence is insufficient to determine the balance of benefits and harms of routinely screening every asymptomatic, nonpregnant adult for thyroid dysfunction.

That distinction is important: a test can be clinically useful without being necessary as universal screening.

What About Vitamin D, Vitamin B12, and Other Nutrients?

Nutrient testing should also be individualized.

Vitamin B12 testing may be useful in certain patients with:

• Anemia

• Numbness or tingling

• Neurologic symptoms

• Gastrointestinal disorders

• Restrictive diets

• Previous gastrointestinal surgery

• Certain long-term medication exposures

Iron and ferritin testing may be appropriate when anemia, blood loss, heavy menstruation, dietary concerns, or compatible symptoms are present.

Vitamin D is frequently measured, but universal vitamin D screening for every healthy adult is not supported by clear evidence.

The USPSTF currently considers the evidence insufficient to determine whether routine screening for vitamin D deficiency improves outcomes in asymptomatic, community-dwelling adults.

This does not mean vitamin D testing is never useful. It means the decision should be based on the individual's circumstances rather than automatically included in every annual laboratory panel.

Do You Need Hormone Testing as You Get Older?

Hormone testing can be useful, but age by itself is generally not enough reason to order a large hormone panel.

For example, testosterone testing may be appropriate when compatible symptoms and medical history raise concern for testosterone deficiency.

Evaluation of reproductive hormones may be useful for selected menstrual, fertility, menopausal, or endocrine concerns.

Hormone results can also be influenced by:

• Time of day

• Menstrual cycle

• Medications

• Hormonal contraception

• Pregnancy

• Acute illness

• Other medical conditions

For that reason, hormone testing is generally most useful when there is a clear reason for ordering it and a plan for how the result will be interpreted.

Your Medical History May Matter More Than Your Age

Age-based recommendations provide a useful starting point, but your personal history can completely change the appropriate testing strategy.

You may need testing earlier or more frequently if you have:

• A family history of premature heart disease

• A family history of diabetes

• High blood pressure

• Obesity

• Kidney disease

• Liver disease

• Thyroid disease

• Autoimmune disease

• Heavy menstrual bleeding

• Previous nutritional deficiencies

• Gastrointestinal disease or surgery

• Pregnancy

• Chronic medication use

• Previous abnormal laboratory results

• Symptoms that require investigation

This is why two people of exactly the same age may appropriately receive very different laboratory orders.

Symptoms Can Change Which Tests Are Appropriate

Preventive screening applies to people who do not have symptoms.

Once symptoms develop, laboratory testing becomes diagnostic rather than simply preventive.

For example, unexplained fatigue could potentially lead to consideration of tests evaluating:

• Anemia

• Iron status

• Thyroid function

• Blood sugar

• Kidney function

• Liver function

• Vitamin B12

• Other conditions suggested by the history

Unexplained weight loss, persistent fever, excessive thirst, abnormal bleeding, jaundice, swelling, weakness, or other significant symptoms may similarly justify testing that would not otherwise be part of routine screening.

The laboratory order should therefore be built around the clinical question rather than the patient's age alone.

More Laboratory Testing Is Not Always Better

Modern laboratories can measure thousands of different biomarkers.

That does not mean measuring all of them produces better healthcare.

Unnecessary testing can create problems of its own.

The more tests performed on a healthy person, the greater the likelihood that at least one result will fall slightly outside a laboratory reference range simply by chance.

This can lead to:

• Unnecessary repeat testing

• Additional costs

• Anxiety

• Incidental findings

• Further testing that may not improve health outcomes

A thoughtful laboratory strategy focuses on tests that have a reasonable clinical purpose.

For a broader comparison, read Routine Blood Work vs. Specialty Laboratory Testing.

How Often Should Your Laboratory Tests Be Repeated?

There is no universal answer.

Some tests may only need to be performed once.

Others may be repeated every few years.

Still others may need monitoring every several months—or even more frequently—when managing a medical condition or medication.

Factors that influence testing frequency include:

• Your age

• Previous results

• Medical conditions

• Family history

• Medications

• Symptoms

• Pregnancy

• Treatment changes

• Cardiovascular and metabolic risk

• Whether an abnormality is being monitored

A healthy 25-year-old with consistently normal results may require far less testing than a 55-year-old with diabetes, hypertension, kidney disease, and several medications.

Learn more in How Often Should I Have Routine Blood Tests?.

Think in Terms of a Personal Laboratory Timeline

Rather than asking, “What blood tests should everyone my age get?” a more useful question may be:

“Given my age, history, family risks, medications, symptoms, and previous results, what information would be useful to know now?”

Your personal laboratory timeline may include:

• Establishing baseline measurements when appropriate

• Completing recommended one-time screenings

• Repeating cardiovascular and metabolic testing at appropriate intervals

• Monitoring chronic conditions

• Monitoring medications

• Investigating new symptoms

• Following previous abnormalities

• Adjusting testing as your health changes

Over time, your previous laboratory results become part of your medical history.

That makes thoughtful trend analysis increasingly valuable.

Preparing for Age-Appropriate Laboratory Testing

Once you and your physician decide which tests are appropriate, preparation can influence the accuracy of certain results.

Depending on the tests ordered, instructions may involve:

• Fasting

• Hydration

• Medication timing

• Supplement use

• Exercise

• Time of day

• Menstrual-cycle timing

• Other test-specific considerations

Do not stop prescription medications or supplements unless your healthcare professional specifically tells you to do so.

If you are preparing for blood work, read How to Prepare for Your Laboratory Appointment for additional guidance.

Frequently Asked Questions

Should everyone have blood work every year?

No. There is no universal laboratory schedule that applies to every healthy adult.

Some patients benefit from yearly testing, while others may appropriately be tested less often. People with chronic medical conditions, medications requiring monitoring, previous abnormalities, or changing symptoms may require more frequent testing.

What are the most common preventive blood tests?

Depending on the patient, commonly considered tests may include a lipid panel, glucose or A1C, CBC, metabolic testing, and selected infectious-disease screening.

However, being commonly ordered does not mean every test is necessary for every patient.

Should I request every possible laboratory test?

Usually not.

Testing is most useful when there is a clinical reason for ordering the test and the result has a reasonable chance of influencing your care.

Does a normal blood test mean I am completely healthy?

No.

Laboratory testing is only one part of a medical evaluation.

Many health conditions are evaluated through medical history, physical examination, blood pressure, imaging, age-appropriate cancer screening, and other forms of assessment that may not involve blood testing.

Likewise, a result inside the laboratory's reference range does not always mean it is optimal or appropriate in every clinical situation.

Does an abnormal laboratory result mean I have a disease?

Not necessarily.

Laboratory results can be influenced by hydration, recent illness, medications, exercise, diet, pregnancy, timing, biological variation, and other factors.

Your physician considers the degree of abnormality, related measurements, symptoms, previous results, and medical history before determining what a result means.

Can I ask my physician which tests I should have for my age?

Absolutely.

A useful preventive-care discussion can include your age, family history, previous results, medications, lifestyle, reproductive history, cardiovascular risk, and personal concerns.

The goal should be to create a testing strategy appropriate for you rather than simply ordering the largest available panel.

The Bottom Line

Laboratory testing changes throughout life, but age should guide testing—not dictate it.

Young adults may benefit from establishing important cardiovascular and infectious-disease screening baselines. During the 30s and 40s, diabetes and cardiovascular risk become increasingly important. In the 50s, 60s, and beyond, chronic disease risk, medication monitoring, kidney function, metabolic health, and trends over time often deserve greater attention.

Pregnancy, symptoms, medical conditions, medications, and family history can change the testing strategy at any age.

The best laboratory plan is therefore not the one with the most tests.

It is the one that provides useful information for your health at your current stage of life.

For additional education, explore our Routine Laboratory Testing Resources or learn how laboratory testing can be incorporated into a broader Preventive Care & Health Optimization evaluation.

Medical Review & Evidence Standards

This patient guide is intended to provide general education about preventive and age-appropriate laboratory testing. It does not establish a universal testing schedule and should not replace individualized medical advice.

Recommendations and medical information were reviewed using authoritative sources and contemporary preventive-care guidance, including:

• U.S. Preventive Services Task Force — evidence-based preventive screening recommendations

• Centers for Disease Control and Prevention — recommendations regarding hepatitis, HIV, sexually transmitted infections, and pregnancy-related screening

• American College of Cardiology and American Heart Association — 2026 guidance regarding cholesterol, cardiovascular risk assessment, and lipoprotein(a)

Screening recommendations can change as evidence evolves, and individual medical circumstances may justify testing earlier, later, or more frequently than general population recommendations.

Written by YiQiu Hu, NMD
Arizona-licensed naturopathic physician
Updated August 2026

About the Author

YiQiu Hu, NMD

Dr. YiQiu Hu is an Arizona-licensed naturopathic physician, founder of Ask Dr. Hu, and medical director. He provides personalized concierge medicine, preventive healthcare, health optimization, diagnostic evaluation, laboratory assessment, and individualized medical care for patients throughout Arizona.

Dr. Hu's approach emphasizes thoughtful medical evaluation, careful interpretation of laboratory results, preventive healthcare, evidence-informed treatment options, and long-term physician-patient relationships.

He earned his Doctor of Naturopathic Medicine degree from Sonoran University of Health Sciences and a Bachelor of Science in Biomedical Sciences from Northern Arizona University.

Patients interested in developing an individualized preventive laboratory strategy can learn more about Preventive Care & Health Optimization or explore additional Routine Laboratory Testing Resources.

This article is for general educational purposes and does not replace individualized medical advice, diagnosis, or treatment.