This panel contains the following tests:

• Absolute natural killer cells
• Percentage of natural killer cells
• Complete blood count (including absolute lymphocyte count)

Natural killer (NK) cells are highly selective white blood cells found in our immune system. They patrol the body looking for cells that are infected with cancer or other viruses. NK cells recognize and kill these infected cells and are able to defend us from infection and/or prevent the progression of disease. The number and function of NK cells are generally measured to monitor the baseline of immune function, the effect of treatment, and/or the progression of metastatic cancer.

Cells in our immune system are characterized by unique markers (antigens) on their surface membranes called CD proteins. CD molecules can act in many different ways and are often used to associate cells with different immune functions. NK cells are classified as being positive for CD56 and negative for CD3. In other words, they express NK cell markers with a 95% confidence level; they do not express T cell markers.

Instructions

Fasting is not required for this test. Take all medications as prescribed. This test should be drawn Monday through Wednesday only. It must arrive at the testing laboratory in less than 48 hours in order to preserve cell viability. Due to the limited viability of these cells, we cannot offer this test in a blood draw kit. The blood must be drawn at a LabCorp Patient Service Center or at the Life Extension Nutrition Center.

Note

This test does not measure the function of natural killer cells - it measures the quantity.