You’re at your annual physical and your doctor writes a script for some lab work. So, what is your doctor looking for? The truth is, many people don’t ever know.
You see, when your doctor writes the script, he checks off a lot of boxes that tell the lab what specific tests to run. Depending on your age, medical history, risk factors, symptoms and family history, your doctor customizes your lab tests to glean important information about your health, and if necessary, help diagnose and manage health conditions.
Your lab work tells your doctor important things about your health.
When your body is healthy, there are specific levels (or ranges of values) that indicate a balance of fluids, chemicals and hormones. If you have a disease or condition, these levels can change and cause symptoms. Lab tests and profiles are important because they can help to find these imbalances and lead to treatments to restore your optimal health.
Now, after you get your blood drawn, that tiny little tube gets sent to the lab, where it is evaluated with a report that is sent to your doctor. If your results are in a healthy range, you might never see your numbers. So, it’s important to actively seek them and keep records of your health throughout all of life’s stages.
So, here are four important lab tests and numbers to know.
Taking an active role in your health is important. If you track your own numbers over time, you might start identifying trends — even if changes occur within healthy ranges — you can talk with your doctor about them. For example, if you see your cholesterol went up towards the higher range of normal compared to last year’s values, you might talk to your doctor about your diet and exercise routine and work together to make healthier choices.
While your doctor will personalize lab tests for you, these are some common tests to talk with your doctor about and keep handy for your records.
1. Complete Blood Count (CBC)
A CBC is a blood test that gives your doctor a good picture of your overall health. It can measure different components and features of your blood, including:
- The number and size of red blood cells (these cells carry oxygen)
- The number of white blood cells (these cells help fight infection)
- Total amount of hemoglobin and amount per red blood cell (this protein carries oxygen in red blood cells)
- Fraction of hematocrit (this is the proportion of red blood cells to fluid component, or plasma, of the blood)
- Total number of platelets (these cells help blood to clot)
According to Florida Hospital Laboratories, the normal value ranges for these cells are the following:
Red blood cell count (RBC):
Male 4.0 to 5.65 10*3/uL
Female 3.75 to 5.0 10*3/uL
White blood cell count (WBC):
4.40 to 10.50 cells 10*3/uL
Male: 36.9% to 48.5%
Female: 34.3% to 45.5%
Male 12.6 to 16.7 g/dL
Female: 11.4 to 14.7 g/dL
139 to 361 10*3/uL
These are just a few of the important values a CBC can tell your doctor about your health. If any of your cell counts in the CBC are abnormal, it helps your doctor to determine if you have an underlying medical condition, such as anemia, infection or cancer and what further testing is needed.
2. Comprehensive Metabolic Panel
A Comprehensive Metabolic Panel is a group of blood tests that tell your doctor about your body’s chemical balance, fluids and metabolism function. This panel is able to be performed both fasting and non-fasting. If fasting is requested by your physician, it means no eating or drinking for at least eight hours before the test.
A metabolic panel can tell you doctor about the following in your body:
- Kidney and liver function
- Blood sugar
- Calcium levels
- Sodium, potassium and chloride levels (electrolytes)
- Protein levels
While the Comprehensive Metabolic Panel can test more values, some of the most common tests with their normal values are below.
- Potassium: 3.5 to 5.0 mmol/L
- Sodium: 135 to 145 mmol/L
- Chloride: 98 to 110 mmol/L
- Glucose: 70 to 100 mg/dL
- Calcium: 8.5 to 10.5 mg/dL
- BUN (blood urea nitrogen): 5 to 25 mg/dL
- CO2 (carbon dioxide): 24 to 32 mmol/L
- Albumin: 3.2 to 5.5 g/dL
- Total protein: 6.0 to 8.0 g/dL
- Total bilirubin: 0.1 to 1.5 mg/dL
- Alkaline phosphatase: 14 to 127 U/L
- ALT (alanine aminotransferase): 4 to 51 U/L
- AST (aspartate aminotransferase): 5 to 46 U/L
If you have abnormal results with your Comprehensive Metabolic Panel, your doctor might order additional tests to determine the cause. For example, if you have high blood glucose, you might need further diabetes screenings.
3. Lipid Panel (Cholesterol Test)
A lipid panel can tell your doctor about substances in your blood that carry cholesterol, which when above normal levels, can increase the risk for heart disease over time. This test often requires you to keep from eating or drinking up to twelve hours before it.
Some of the tests in a lipid panel include:
- Total cholesterol (this measures the total cholesterol in your blood, including LDL, HDL)
- LDL (bad) cholesterol (LDL is the main source of cholesterol buildup/blockage in the arteries)
- HDL (good) cholesterol (HDL helps to remove cholesterol from your arteries)
- Triglycerides (a form of fat in the blood that can increase heart disease risk)
The NIH states that the optimal values for cholesterol are the following:
- Total cholesterol: less than 200mg/dL
- LDL: less than 100mg/dL
- HDL: 60 mg/dL and above is considered protective against heart disease
It’s important to monitor your cholesterol levels over time because they could identify risk factors for heart disease, many of which can often be reduced with lifestyle factors like diet and exercise, and if needed, prescribed medications that are routinely monitored by your doctor.
4. Thyroid Screen
Your thyroid gland plays an important role in your metabolic function and can affect every organ in your body. That’s why it’s common for a basic thyroid screen to be included in your routine blood work.
There are several different tests to show the function of different thyroid hormones and antibodies, but the most common routine thyroid screen that could first alert a thyroid problem is the thyroid stimulating hormone (TSH) test. Made by the pituitary gland, TSH alerts your thyroid gland to produce it’s two hormones (T3 and T4).
Florida Hospital Laboratories indicates a normal healthy range for TSH is 0.4 to 4.5 uIU/mL.
If your TSH level is too high or low, your doctor might order some other blood work to test the levels of T3, T4 and thyroid antibodies, which could indicate an autoimmune thyroid disorder.
You see, the lab plays a very important role in helping your doctor monitor and support your health and well-being. And you play a big part too by staying up-to-date with your numbers, your routine doctor exams, recommended screenings, tests and lab work.