Natural Killer (NK) Cytotoxicity Profile
Method Description Describes how the test is performed and provides a method-specific reference
Natural Killer (NK) Cytotoxicity Profile:
NK cell cytotoxic functional activity is estimated by a standard 4-hour stimulation of effector cells (patient or control peripheral blood mononuclear cells) incubated with target cells (monocytic cell K562 lacking major histocompatibility complex class I expression) labeled with 51Cr. The % cytotoxicity (51Cr release) is measured for a series of effector to target concentrations. Maximal cytotoxicity is measured using a detergent for target cell lysis as an experimental control and spontaneous cytotoxicity in the absence of effector stimulation is also measured.(Unpublished Mayo method)
T- and B-Cell Quantitation by Flow Cytometry:
The T- and B-cell surface marker assay uses monoclonal antibodies to identify the various membrane antigens, and flow cytometry to enumerate the number of cells expressing these differentiation antigens. The results are reported as the percent of lymphocytes that are T-helper (CD3+, CD4+), T-suppressor (CD3+, CD8+), natural killer (CD16+56+, CD3-), and B-lymphocytes (CD19+), and the absolute number of each cell type per mL of blood. The assay is a 4-color, no-wash procedure and the absolute counts are calculated from internal bead standards. In addition, the total lymphocyte count and the helper-suppressor ratio (T[H]/T[S]) is reported.(Hoffman RA, Kung PC, Hansen WP, Goedstien G: Simple and rapid measurement of human T lymphocytes and their subclasses in peripheral blood. Proc Natl Acad Sci USA, 1980:77:4914-4917; US Department of Health and Human Services: Guidelines for performance of CD4+ T-cell determinations in persons with human immunodeficiency virus infection. MMWR Morb Mortal Wkly Rep 1997;46[no. RR-2]:1-29)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
N.K. Cytotoxicity: Monday through Friday; Continuously to 2 p.m.
T- and B-Cell QN by Flow Cytometry: Monday through Sunday
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Performing Laboratory Location The location of the laboratory that performs the test