This test measures the number of white blood cells in your blood. When you get sick, your white blood cell count is higher than normal because your body is releasing more of these cells to fight the infection.

This is a blood test that checks for West Nile virus, an infection that usually affects birds. It can be spread to people through the bite of an infected mosquito.

This test measures the amount of trypsinogen in the blood. Trypsinogen is secreted by the pancrease to help with digestion.

This test looks for a parasite that can infect an unborn child. A pregnant woman can pick up this parasite by eating undercooked meat, drinking contaminated water, or handling cat feces.

This test measures the amount of copper in your blood. Too little or too much copper can cause health problems.

The TORCH panel test is used to help diagnose infections that could harm the unborn baby during pregnancy.

This test checks for proteins in the cerebrospinal fluid to help healthcare providers diagnose Alzheimer disease.

This test looks for a substance that can appear in your blood if you have hairy cell leukemia.

This test measures the level of the hormone thyroxine (T4) in your blood. This test can show your healthcare provider whether your thyroid gland is overactive (hyperthyroidism) or underactive (hypothyroidism).

This test looks for antibodies that your body made when in fighting off group A Streptococcus bacteria. These bacteria cause strep throat.