Natural Killer Cells Test
This test measures the number of natural killer (NK) cells in a whole blood sample using flow cytometry. Quest describes NK cells as a type of white blood cell, with low numbers found in people who are more susceptible to certain viral infections.
About this test
Natural killer cells are a type of white blood cell. This test counts them directly in a whole blood sample using flow cytometry, a method that identifies and counts cells based on markers on their surface.
Quest notes that low numbers of NK cells are found in individuals who are more susceptible to viral infections, including cytomegalovirus and varicella. The test reports a cell count; a clinician reads that count alongside the person's history and other findings.
Test details
| Collection | Quest patient service center |
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Quest resources
Additional details
What this test looks at
The test reports three values from the same whole blood sample: the absolute lymphocyte count, the percentage of cells with the NK cell markers CD3-/CD16+CD56+, and the absolute count of natural killer cells. Reporting the count alongside the percentage and total lymphocytes gives a clinician more than one way to look at the result.
This test isn't part of the Celio Health store at the moment, so it can't be ordered or requested here. The test menu lists everything that can.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does this test measure?
It measures the number of natural killer (NK) cells in a whole blood sample, using flow cytometry.
How is the sample collected?
Through a routine blood draw that collects 5 mL of whole blood into an EDTA (lavender-top) tube.
Do I need to prepare for this test?
No preparation instructions are listed for this test, though people follow any instructions their ordering clinician provides.
Why would a clinician check NK cell numbers?
Quest notes that low numbers of NK cells are found in individuals who are more susceptible to viral infections, including cytomegalovirus and varicella, which is one reason a clinician may look at this count.
What results does the test report?
It reports the absolute lymphocyte count, the percentage of NK cells, and the absolute NK cell count, all from the same blood sample.