How to Understand Your Blood Test Results

Blood tests are important in modern medicine to help doctors diagnose conditions and determine the most effective treatments. With the advancement of technology, blood tests have become more reliable, accessible and affordable.

If blood test results confuse you, you’re not alone. We’ll clarify common tests and what your results mean.

Why are blood tests important?

Blood tests help prevent and find health problems. Doctors avoid ordering unnecessary tests, but basic blood tests can show your overall health, detect issues like anemia, diabetes or infections, and guide treatment – together with your medical history and previous tests. Knowing your results can help you take care of your health.

Common blood tests and what they mean

What is a complete blood count (CBC)?

The complete blood count is one of the most frequently ordered blood tests. It measures white blood cells (WBCs) that help detect infections or conditions like cancer, if the count is too high or too low. It also measures red blood cells (RBCs) that indicate anemia or other blood disorders, hemoglobin, which measures the oxygen-carrying capacity in the blood, and platelets that assess the blood's clotting ability.

Typically, the white blood cell count ranges from three to 12. Hemoglobin should be greater than 12 for women and 14 for men. Platelet counts above 150 are preferred.

What does a comprehensive metabolic profile (CMP) test for?

Key elements of this test include sodium (Na), chloride (Cl), and potassium (K) levels, which reflect hydration and electrolyte status. A fasting sample also pinpoints glucose issues, such as diabetes, if levels exceed 100.

In addition, creatinine (Cr) and blood urea nitrogen (BUN) are important factors in determining your hydration status and how well your kidneys are doing. This leads to a glomerular filtration rate (GFR) that indicates if the kidneys are suffering from chronic kidney failure. The panel also examines liver function through bilirubin, AST/ALT and alkaline phosphatase, which can detect early signs of fatty liver disease or damage caused by medications.

What is the purpose of a urinalysis (UA)?

This common test checks hydration through urine gravity and detects abnormalities based on color and pH. Its main focus is to identify leukocytes or nitrites for infections, glucose for possible diabetes, and protein or blood as early indicators of cancers or kidney disease.

How do thyroid tests work?

Thyroid tests measure hormones like TSH, T3 and T4 to detect thyroid disorders. High T3 and T4 can lower TSH, indicating hyperthyroidism. Low T3/T4 usually raises TSH, suggesting hypothyroidism. Not all thyroid tests show T3 and T4 as these measures are only ordered as a reflex to an abnormal TSH test.

What is a cholesterol or lipid panel?

A lipid panel helps indicate your risk for heart disease and inflammation, but it can be challenging to understand. This is a very common test that can often be difficult to understand. The test is broken down into:

• Total cholesterol (TC): Overall cholesterol levels
• High-density lipid (HDL): Commonly called the “good” cholesterol
• Low-density lipid (LDL): Commonly called the “bad” cholesterol
• Triglycerides: Related to what you eat and inflammation
• Total cholesterol to high-density lipid ratio (TC/HDL ratio) 

The greatest factor in risk is the absolute number of low-density lipid. Numbers greater than 130 are concerning, while those less than 100 are excellent. High-density lipid (HDL) is another important factor, as it protects us from harm caused by other types of cholesterol. Ideally, numbers that are greater than 60 are best, whereas numbers less than 40 are considered abnormal.

Triglycerides are important because they play a role in inflammation and are more closely linked to our dietary habits. Numbers less than 150 are excellent, while those greater than 500 become truly worrisome. The ratio is very important in assessing risk. A number greater than five indicates that the patient is at an increased risk.

What does the Hemoglobin A1C test measure?

A hemoglobin A1C test shows the glucose (sugar) pattern over the past two to three months. It is a number given as a percentage that physicians use to help determine if diabetes is present and whether the patient is at risk or normal. A figure greater than 6.5% indicates diabetes, while figures between 5.7% and 6.5% indicate prediabetes.

It’s important to remember that blood tests are rarely a diagnosis on their own. Your healthcare provider will consider your medical history, physical exam and symptoms to interpret the results. From there on, they can create a plan to improve your health.

How often should I get a blood test?

Your provider determines the test frequency based on your age, health history, and risk factors. Routine testing is typically performed annually; your provider may recommend more frequent checks if necessary.

What should I do if my results are abnormal?

Abnormal results don’t always mean something is wrong. Your provider will review your medical history and conduct additional tests to determine the next steps.

Can I interpret my blood test results on my own?

Understanding the basics of your blood test is helpful but consult your healthcare provider for a comprehensive interpretation.

If you have questions about your results, contact your provider. Together, you can work toward the best possible health outcomes.