Types of blood tests to screen

When you have a screening blood test at the doctor’s office, a number of tests are performed. Each doctor chooses which things to screen for but, in many cases, there are chemistry panels and full blood counts (FBCs) that allow the doctor to screen for many different diseases at once. Such a screening test is usually done once per year on a fasting basis for older individuals and is done less often for people under age 50 years.

The different things that are screened for include liver, kidney and metabolic diseases as well as diseases of the blood and thyroid. Let’s take a look at the screening tests which are done:

1. Electrolytes screen for a number of things including kidney and metabolic disease. This includes the potassium, sodium and chloride levels.
2. Urea and creatinine are tests of kidney function. Usually they go up together but, in the case of things like dehydration, the Urea can be elevated but the creatinine is normal. The creatinine is the best test for kidney disease itself.
3. SGOT, SGPT are tests of liver function. These are liver enzymes that go up if the liver is inflamed. The SGPT is considered more sensitive for liver inflammation but both tests are assessed.
4. Bilirubin is a byproduct of red blood cell metabolism in the liver. There is a direct bilirubin and an indirect bilirubin but the screening test just measures the total bilirubin. Further testing can break down the direct and indirect bilirubin.
5. Fasting glucose. This is a good screening test for diabetes. The normal fasting glucose level is less than a hundred. Between 100 and 125 mg/dL is pre-diabetes or possible impending diabetes. Above 125 mg/dL, diabetes is strongly suspected. An oral glucose tolerance test (OGTT) is used to define true diabetes or an HbA1C can be used to further define the diagnosis of diabetes.
6. Uric acid is a screening test for gout. A person can have a high uric acid level and not have gouty symptoms but will be at risk for gout.
7. Total protein, albumin and globulin are tests for how malnourished a person might be. If the albumin and total protein are low, there may be malnourishment. An elevated globulin level is seen in some blood cancers.
8. A FBC and differential screens for anemia, leukemia and platelet disorders. This is a good test to do if someone is feeling tired or out of sorts.
9. · TSH is a measure of thyroid function. The TSH is made by the pituitary gland and is increased if the thyroid gland function is low.