US · guidance
CMS SOM App. C, Tag D5465
§493.1256 Standard: Control procedures
(d)(8) Test control materials in the same manner as patient specimens.
Interpretive Guidelines §493.1256(d)(8)
Control materials of a similar matrix to that of patient specimens should be utilized, if
available, and the control materials must be treated in the same manner as patient
specimens and go through all analytic test phases.
Flow Cytometry
In cell surface phenotyping by flow cytometry or fluorescent microscopy, control
samples must be analyzed within the same time period after staining as test specimens.
Probes §493.1256(d)(8)
Flow Cytometry
How did the laboratory establish the time period in which stained cells must be analyzed
to avoid significant loss of any cell subpopulations or total cell numbers?
If analysis will be based on a population of cells selected by flow cytometry “gating” on
size or density parameters, or selected by depletion or enrichment techniques, are controls
tested with each patient to detect the presence of contaminating cells in the selected
population? (e.g., Monocyte contamination of “lymphocytes” gated by forward angle or
forward angle versus 90° light scatter must be detected with a monocyte-specific
antibody.) Use D5465 or D5425 as appropriate.
History
Rev. 233; Issued: 09-12-25; Effective: 09-12-25; Implementation: 09-12-25
Provenance
- Source
- cms.gov
- Retrieved
- 2026-07-22
- Edition
- som-2026-07-22
- Content hash
eac113ebc1dcf9f63fd83e824c1c63c285595a18616b9fcc38a9e07d7de1edd6
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