Common Lab Tests Explained: Reasons for Testing and Test Preparation

Common Lab Tests Explained: Reasons for Testing and Test Preparation
Page content

Cholesterol Test

Several common blood tests can provide your doctor with an assessment of your health even if you are not showing symptoms. The cholesterol test measures your total cholesterol, your HDL or good cholesterol, and your LDL or bad cholesterol. Triglyceride levels are also included to provide a more complete assessment of your blood lipid levels.

You will need to fast before receiving this blood test for the most accurate results. If you do not have a history of high cholesterol, your doctor may order this test every five years. Your doctor may recommend annual tests if you have tested high for total cholesterol, LDL, or triglycerides.

The purpose of the test is to determine your risk of heart disease. Atherosclerosis or hardening of the arteries is a major risk factor for developing this condition which is the leading cause of death in the United States. When considering common lab tests explained in this article, the cholesterol test may be one of the most important.

Blood Sugar Test

A blood sugar or glucose test assesses your risk for developing diabetes. If you have other issues with blood sugar such as hypoglycemia, your doctor may also call for this test. Pregnant women may be tested between their 24th and 28th weeks of pregnancy to rule out gestational diabetes.

Like the cholesterol test, the most accurate results occur if you have fasted prior to testing. Glucose can be determined through a blood test or as part of an urinalysis. Blood sugar is regulated by hormonal activity of the pancreas. The test determines if your levels are within a healthy range.

Blood tests are preferable to urine tests because of the accuracy of the results. High glucose levels over 99 mg/dL may indicate pre-diabetes. Your doctor will collect a thorough history to rule out other conditions which may cause elevated levels.

Liver Profile

A liver profile looks at liver function. Because of the variety of processes it performs, any impairment in its function can be a red flag for further investigation. Your doctor may order annual screenings if you are on statin drugs for treating high cholesterol. Signs of liver disease such as weakness or jaundice may also prompt your doctor to call for a liver profile. It is often included as part of pre-op blood work.

These drugs, while effective, may impair liver function. Unlike the other two tests, you do not have to fast prior to this blood test. The test measures the levels of several enzymes necessary for liver health. It will also asses the levels of essential proteins including antibodies.

A discussion of common lab tests explained in this article should also include mention of the turnaround time for testing. While some tests can be completed in house, other tests may be sent out to a laboratory for detailed analysis. Most test results will give clear indications if the tested levels are within the normal range. Your doctor can provide additional information regarding your lab tests.


American Diabetes Association: Hypoglycemia (Low blood glucose)

American Association for Clinical Chemistry: Liver Panel

Mayo Clinic: Cholesterol levels: What numbers should you aim for?

Photo by Griszka Niewiadomski, stock.xchng