What a Blood Test Can Reveal About Your Health

What a Blood Test Can Reveal About Your Health


Your doctor can learn a lot about you from a simple blood sample. In fact, patterns in your blood work can even uncover your heritage and genealogy.

To learn more about what a blood test can tell doctors about your health, we spoke with Dr. Jordan Conway, primary care physician at St. Joseph and Texas A&M Health Network in Navasota.

Before we jump in, let’s look into what all makes up your blood.

What are the different components of blood?

  1. Plasma. This contains water, sugars, fats, cholesterol, protein, and salts.
  2. Red Blood Cells (RBCs). These cells carry oxygen in our blood by the protein hemoglobin. The hematocrit test measures the percentage of RBCs in your blood.
  3. White Blood Cells (WBCs). These cells fight infections.
  4. Platelets. These help clot our blood when we get a cut.

What are some common blood tests?

Complete Blood Count

This test evaluates the amount of the various cells in your blood. If your WBC count is high, it could indicate infection, but if it’s low, you may have a deficiency in your WBC production. If your hematocrit or hemoglobin concentration is low, then you are considered anemic. And if your platelet count is low, your blood might not clot as it should.

Complete Metabolic Profile (CMP)

The CMP analyzes 14 substances in your blood:

  • Glucose
  • Calcium
  • Albumin (a protein produced by the liver that indicates malnutrition if levels are low)
  • Total protein
  • Sodium
  • Potassium
  • Bicarbonate (Total CO2)
  • Chloride
  • Blood urea nitrogen (BUN)
  • Creatinine
  • Alkaline phosphatase (ALP)
  • Alanine aminotransferase (ALT, SGPT)
  • Aspartate aminotransferase (AST, SGOT)
  • Bilirubin

Based on your levels, your doctor can determine whether you are deficient in key nutrients and how well your organs function, particularly your kidneys and liver.

Lipid Panel

This test calculates your total cholesterol level, which is key to determining your risk of heart disease and stroke. It takes a look at your HDL, LDL, and triglyceride levels.

Hemoglobin A1c

This common test is used to diagnose and monitor diabetes. It measures the level of A1c protein, which is located on the hemoglobin. Because the life-cycle of a RBC is 90 days, this measurement gives us a 90-day average of the patient’s blood sugar levels.

Thyroid-Stimulating Hormone (TSH)

The TSH test evaluates your thyroid function. If your TSH levels are low, you may have hypothyroidism. If your levels are high, you may have hyperthyroidism.

Why is it important to get blood work done?

Routine lab work can help physicians find early signs of infection or poor organ function before they become major problems in the patient. For example, we routinely look at kidney function through the CMP. If the patient’s kidney function is gradually decreasing, we can adjust their medications and diet to help prevent further damage or refer them to a kidney specialist, known as a nephrologist.

What factors besides disease can cause abnormal blood test results?

Certain lifestyle factors can impact your blood test results. Consuming sugary or fatty foods before coming to give blood can falsely raise your glucose or lipid levels, which is why these tests require fasting beforehand. Additionally, smoking can raise your hemoglobin and hematocrit levels, and dehydration can interrupt the results used to determine kidney function.

Ask your primary care physician if you’re due for a routine blood test. Schedule a same or next-day appointment at your nearest St. Joseph and Texas A&M Health Network clinic.

Sources:
American Society of Hematology
American Academy of Family Physicians

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