NK cell function, also called NK cell activity, indicates how well your body can defend itself against dangerous foreign cells. NK cell activity helps your doctor assess the strength of your immune system for fighting off infections or cancer cells.
NK cell activity has been shown to be affected in a number of conditions and diseases. For example, people who are highly stressed or who are not sleeping or eating well may have lower NK cell activity. In elderly patients, low NK cell activity has been associated with an increased risk of infections and other diseases.
Determining NK cell activity is just as important as performing other blood tests, such as a complete blood count.
Measuring NK cell activity does not tell your doctor if you have a disease or an illness; it does, however, help him or her decide what other types of tests you may need to have done.



In the past few decades, many studies have demonstrated that NK cell activity is much lower in individuals with different types of cancers.

NK cell activity has been shown to be lower in patients with the following kinds of cancer:

» Breast
» Prostate
» Colon
» Lung
» Ovarian
» Stomach
» Pancreatic
» Testicular
» Liver
» Thyroid
» Skin
» Hodgkin’s lymphoma
» Non-Hodgkin’s lymphoma
» Multiple myeloma
» Tumours of the head and neck

NK cell activity tends to be lower in healthy individuals whose parents, siblings or other family members have cancer. This reality suggests that low NK cell activity is an important risk factor for the development of a variety of cancers. This theory has been confirmed in a study that followed more than 3 000 people for a span of 11 years, and in which low NK cell activity was used to predict the risk of cancer.

People with a genetic predisposition to low NK cell activity may be at higher risk for developing cancer.
Nevertheless, if your doctor finds that your NK cell activity is very low, this does not mean you have cancer. Rather, it may just signal that you are at higher risk for cancer or that you have an unrecognized infection. Your doctor will discuss your test results with you and decide (based on your family history, symptoms and risk factors) whether you should be retested or have additional tests.
Speak to your doctor to learn more about NK cell activity.


NK cell activity is measured with a simple and affordable blood test. At the blood collection centre or medical clinic, a nurse or technician collects 1 mL of blood for the test.

NK VUE has been studied in clinical trials in Korea and Canada



The correlation between low NK cell activity (as measured by NK Vue) and the presence of colorectal cancer has been demonstrated in a published clinical trial. In a study of 41 patients with newly diagnosed colorectal cancer, researchers at Yonsei University College of Medicine in Korea discovered that the NK cell activity of patients in their study group was significantly lower than it was in the 41 healthy patients in the control group.1
In Canada a study was conducted at Maisonneuve-Rosemont Hospital in Montreal, Quebec, Canada by Dr. Gilles Jobin and colleagues. 1047 successive subjects >40 years of age, who underwent colonoscopy, were recruited between October 2014 and January 2016. NK Vue a novel in vitro diagnostic device (IVDD), was used to measure NKA in these subjects. NKA was compared in subjects with cancer-negative colonoscopies to those with pathologically confirmed CRC. Briefly, in the 762 evaluable subjects, statistically significant differences were found between the NKA of patients positive for CRC (n=21), confirmed by colonoscopy and pathological verification, and that of patients negative for CRC (n=741) (CRC mean 344.2 pg/mL, CRC-negative mean 731.5 pg/mL, p=0.001; CRC median 87.0 pg/mL, CRC-negative median 294.8 pg/mL, p<0.001). At a cut-off of 200 pg/mL, sensitivity of the IVDD for the detection of CRC was 85.7%, with a specificity of 59.6%, with positive and negative predictive values of 5.7% and 99.3% respectively.2



The correlation between low NK cell activity (as measured by NK Vue) and the presence of prostate cancer has also been demonstrated in a published clinical trial. In a study of 54 newly diagnosed, biopsy-confirmed prostate cancer patients, researchers at Yonsei University College of Medicine in Korea found that NK cell activity in these patients was significantly lower than it was in the 54 healthy individuals in the control group.3


1. Lee, S.-B. et al. A high-throughput assay of NK cell activity in whole blood and its clinical application. Biochem. Biophys. Res. Commun. 2014 Mar 14;445(3):584–590.

2. Jobin, G. et al. Tu2088 A New Blood Test for the Detection of Colorectal Cancer (CRC): Measurement of Natural Killer Cell Activity (NKA) in Patients Undergoing Colonoscopy. Gastroenterology 150, S1270–S1271 (2016).

3. Koo, K. C. et al. Reduction of the CD16(-)CD56bright NK cell subset precedes NK cell dysfunction in prostate cancer. PLoS ONE. 2013 Nov 4;8(11):e78049.



If your NK cell activity is low, your doctor may want to further investigate the reasons for this. He/she may recommend lifestyle changes such as diet, exercise, or smoking cessation to help improve your immune system.
If you are over the age of 50, your doctor will assess the possible reasons for your low NK cell activity and review your risk factors. He/she may also decide to order certain screening tests.
If you are a man:
» PSA test and/or digital rectal exam to look for prostate cancer.
If you are a woman:
» Mammogram, and sometimes ultrasound, to look for breast cancer.
For men and women
» Stool test and/or colonoscopy to look for colon cancer.
Based on your test results, your doctor will determine whether further tests are required.
Not all patients want to follow their doctor’s advice when it comes to recommended screening tests: some patients are uncomfortable with the stool test, others are afraid of colonoscopies, while some women do not like mammograms.
It is important to keep in mind that knowing your NK cell activity helps your doctor to better understand your situation, therefore these tests are important.
It is recommended that you follow your doctor’s advice.


Based on your NK cell activity results, your doctor may also recommend some lifestyle changes (i.e. weight loss, exercise, diet, smoking cessation), which could help improve your immune system and increase your ability to fight cancer and other diseases. Be sure to speak to your doctor about NK cell activity and what you can do to improve your immune system.



If you have received a prescription for an NK Vue diagnostic test, please visit www.atgencanada.com, or call 1-855-561-4681, or write to info.  We will recommend a blood collection centre or a clinic able to collect your blood sample.


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