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NK Cells

NK (natural killer) cells are the first line of defense (innate immunity) among immune cells. It detects and immediately removes abnormal cells including cancer cells and virally infected cells. It can inhibit proliferation of cancer cells and prevent recurrence.


The active population of NK cells is more important than the number of NK cells in our body. This activity can only be measured through use of KAct test kit.


Therefore it is crucial to maintain a healthy and active population of NK cells within  the body.

NK Cell activity in Immunity, Cancer and Aging

  • Individual with low NK cell activity have been shown in epidemiological studies to be at significant higher risk of cancer.

  • Decreased NK cells activity has been associated with a variety of solid tumors and large tumor burden and development of metastatic cancer.

  • Families with high incidence of cancer have shown reduced NK cells activity compared with control families. 

  • In  elderly, low NK cell activity has been associated with increased risk of infections and associated morbidities.

  • Preservation of NK cell activity has been linked to increased longevity.

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Diagnostic test kit for the measurement of NK Cell Activity 
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Causes for temporary low NK Cell Activity: Drugs [anti-inflammatory painkillers, antibiotics, cholesterol reducers, proton pump inhibitor (PPI), steroids, anti-cancer agents, etc]

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The Advantages of NK-Act Test


  • Measures the activity of NK cells using a small amount of whole blood.

  • Measures both innate and adaptive immune response.

  • Allows accurate (>95%) analysis of the immune system without loss of any immune cells.

  • Allows regular monitoring of the immune system to maintain good health.

  • World-wide approved diagnostic kit.

  • Applicable to all ages and gender.

  • Fasting in not necessary before the test.

Frequently Asked Questions

Q:  Who can take the NK activity test?

A:   Any patient with a disease that is known to affect NK cell activity, such as cancer, OR anyone who wishes to check their immune strength as a health benchmark.

Q:  What are the precautions before having the test?

A:   There are drugs (e.g. steroids) and diseases (e.g. cancer) that may affect the test result, so consultation before testing is necessary.

Q:  How is it different from other NK cell activity tests?

A:   Existing methods of measuring the activity of NK cells require separating NK cells from the peripheral blood mononuclear cells or the use of radioisotopes. The entire process can be difficult and time consuming. However, NKAct service uses a common ELISA method on whole blood so it is easy to get accurate results. In addition, it measures both the cytotoxicity and immunomodulation function of the innate immune system.


Q:  If the activity  of NK cells are low, does that mean I have a disease?

A:  NK cell activity test does not diagnose specific diseases, so a low result doesn’t mean that you have a disease. However, it has been demonstrated in many studies recently that patients with cancer usually have low NK Cell activity, and that patients with low NK Cell activity are at a higher risk of developing cancer or infections.

A person with low NK cell activity should retake the test within 2 to 4 weeks. If a person’s NK cell activity stays low, he or she should consult with a physician to determine if NK cell therapy would be beneficial.


Q:  What are the conditions that may temporarily affect the result?

A:   The drugs you are taking (steroids, anti-cancer agents, immune inhibitors, analgesis, antibiotics, cholesterol reducers, etc.) may affect the results.

If you are taking drugs, consult your physician before the test. Severe sleep disorder, acute stress, poor lifestyle habits, and pregnancy may also affect the test results.

Q:  Why NK cell activity could decrease?


•   Various life style diseases

•   Vulnerable to infectious diseases

•   Physiological stress

•   Chronic fatigue

•   Unhealthy lifestyle

•   History of cancer

•   Exposed to harmful environment

Q:  What are the consequences of decrease in NK cell activity or potential complications?


•   Increased risk of cancer

•   High chances for metastatic cancer

•   Multiple sclerosis

•   Kidney disease

•   Chronic infections

•   Decreased resiliency in recovery from 

•    infection

•   Behavioral / cognitive deficits

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