Common Blood Tests and Why They Are Important

Most people ages 25-60 who visit their primary care provider regularly have blood tests done a few days before their visit.

These blood tests measure different types of cells, proteins, hormones, and other important things in your body. Each number on the chart tells your provider a story about your health, which helps to inform how they make medical decisions with you.

We put together a guide of some of the most common blood tests ordered during a standard annual wellness exam with primary care providers so you can understand why they are ordered and what they tell you (and your provider) about your overall health.

Common blood tests

Comprehensive metabolic panel

A comprehensive metabolic panel measures several important chemical levels in your body, including:

• Albumin
• ALP/ALT/AST
• Bilirubin
• Blood urea nitrogen (BUN)
• Calcium
• Creatinine
• Electrolytes (sodium, bicarbonate, potassium, chloride)
• Glucose (blood sugar)

These levels tell your provider how well your major organs are working. The proteins, enzymes, and other chemicals in this panel measure your heart, liver, kidney, and brain function.

If these levels are abnormal, they could suggest kidney or liver concerns, including diabetes or dehydration.

Complete blood count

A complete blood count looks at all the cells in your blood, including:

• Red blood cells
• White blood cells
• Platelets
• Hemoglobin

Changes with your blood cells can be an early sign that something may not be right in your body, even if you don’t feel any symptoms.

Reviewing a complete blood count can help to determine if someone has an infection, blood disorder, anemia, or an immune condition.

Lipid panel

Lipids are fatty compounds that live in your blood that tell us if we are at risk of developing heart disease or other heart-related conditions. A lipid panel will measure:

• Total cholesterol
• HDL (high-density lipoprotein) cholesterol
• LDL (low-density lipoprotein) cholesterol
• triglycerides

Measuring lipid levels helps to determine whether you might be at risk for developing cardiovascular disease. Higher total cholesterol and triglyceride levels put you at an increased risk of developing heart disease, stroke, and other health conditions.

The earlier your primary care provider can identify these changes, the more proactive they can be about taking steps to get your levels back to a more manageable level.

Hemoglobin A1C

This test measures your blood sugar using the percentage of your red blood cells that have hemoglobin (a protein in your blood) that are coated in glucose (blood sugar).

Because hemoglobin A1C measures your average blood sugar for the last 2-3 months, this test is specifically used to determine if you are at risk of prediabetes or diabetes.

Diabetes can lead to serious health problems, including heart disease, kidney disease, and nerve damage. If you and your provider do regular blood tests, you can identify these issues early and treat them as needed.

Thyroid stimulating hormone (TSH)

Your thyroid is a butterfly-shaped gland that creates hormones that control how your body uses energy. During a TSH blood level test, your provider is looking at a specific hormone called thyrotropin to determine if your thyroid is overactive, underactive, or having other issues.

If your thyroid isn’t working the way it should, you may be experiencing:

• weight gain/loss
• energy level changes
• heart rate changes
• mood swings

Because this hormone level can change slowly, measuring it regularly helps your primary care provider to track it closely and determine if you might have a thyroid condition.

Ferritin

Your ferritin levels measure how much iron you have in your blood. Iron is a key ingredient in helping to make new red blood cells, which carry oxygen from your lungs to the rest of your body.

You might have low ferritin levels if you are short of breath, tired, dizzy, irregular heartbeat, or pale skin. You might have high ferritin levels if you have joint pain, belly pain, lower sex drive, or are feeling tired/weak.

These changes in ferritin levels can be signs of other health conditions, including but not limited to:

• inflammation
• cancer
• obesity
• hyperthyroidism
• liver disease

Vitamin D

Vitamin D supports several important functions in your body, including keeping your immune system, muscles, and nerves working and preventing bone disorders.

People get their vitamin D from three sources:

• sunlight
• food absorption
• supplements

In locations like Rochester, the Finger Lakes, and the North Country, there are fewer days of sunlight compared to other places in the U.S. Not getting enough sunlight can lead to lower vitamin D levels, which may be one reason why your primary care provider would include this as part of your blood testing.

Low vitamin D levels could put you at risk for low bone density, osteopenia, or osteoporosis. If you have muscle aches or bone pain, you may be tested for vitamin D levels.

Normal levels for blood tests

Every person’s version of normal is different based on factors like genetics, BMI, age, sex, preexisting health conditions, and more.

Talking regularly with your primary care provider helps to determine what is normal for you. Once you and your provider have a good idea of what your personal “normal” looks like, it becomes easier to tell if something changes with your health.