{"id":"nk-cells-absolute","name":"CD16+/CD56+ NK Cells, absolute","shortName":"NK cells (absolute)","aliases":["Absolute CD16/CD56","CD16/CD56 Absolute","CD16/CD56 Abs Cnt","CD16/CD56+ Cells, Absolute","NK Cells, Absolute","Natural Killer Cells, Absolute","Absolute NK Cells","NK Cell Count","Natural Killer Cell Count","Ab NK (CD56/16)","Absolute NK (CD56/16)","CD3-CD16+CD56+ Absolute","CD3-CD56+ Absolute","CD16+CD56+ Cells Absolute","Absolute Natural Killer Cells"],"abbreviations":["Abs NK"],"loinc":[{"code":"9728-7","primary":true},{"code":"20402-4","primary":false},{"code":"53936-1","primary":false},{"code":"20604-5","primary":false}],"specimen":"whole-blood","units":[{"ucum":"/uL","display":"cells/µL"},{"ucum":"10*3/uL","display":"×10³/µL"},{"ucum":"10*9/L","display":"×10⁹/L"},{"ucum":"10*6/L","display":"×10⁶/L"}],"referenceRanges":[{"population":"16+","low":24,"high":406,"unit":"/uL","unitDisplay":"cells/µL","note":"Labcorp adult interval for CD3-CD56+ natural killer cells (test 505370, 95% confidence interval). ARUP Laboratories prints 78 to 470 cells/µL for ages 16 to 64 (74 to 620 from age 65), counting cells that carry CD16 or CD56 and lack CD3, so the limits differ between labs. Labcorp's interval is kept because it is one of the two largest US labs and its result code is the primary LOINC code here. Use the range on your own report. Basic T, B and NK cell counts are the usual first flow cytometry step when an inherited immune problem is suspected (Salzer 2019).","sources":[{"title":"T- and B-Lymphocyte and Natural Killer Cell Profile (test 505370)","url":"https://www.labcorp.com/tests/505370/t-and-b-lymphocyte-and-natural-killer-cell-profile","publisher":"Labcorp"},{"title":"Lymphocyte Subset Panel 5 - Total Lymphocyte Enumeration (test 0095892)","url":"https://ltd.aruplab.com/Tests/Pub/0095892","publisher":"ARUP Laboratories"},{"title":"Flow Cytometry in the Diagnosis and Follow Up of Human Primary Immunodeficiencies","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC6893889/","publisher":"EJIFCC (International Federation of Clinical Chemistry and Laboratory Medicine)","year":2019}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"How many natural killer (NK) cells are in a microliter of blood. NK cells are white blood cells that help the body handle viruses and damaged cells.","url":"https://bloodtesttracker.com/markers/nk-cells-absolute","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}