CMS SOM App. C, Tag D5601

(a) As specified in §493.1256(e)(3), fluorescent and immunohistochemical stains

must be checked for positive and negative reactivity each time of use. For all other

differential or special stains, a control slide of known reactivity must be stained with

each patient slide or group of patient slides. Reactions(s) of the control slide with

each special stain must be documented.

Interpretive Guidelines §493.1273(a)

When condition-level deficiencies in Histopathology are identified in any or all phases of

testing, use D5028.

The technical component, preparation of slides (TC) can be prepared in one laboratory

and the finished product sent to another laboratory for professional interpretation (PC).

Both laboratories should show documentation of adequate slide preparation which is

processing, and processing includes the QC of the stain at both locations.

The laboratory must demonstrate that each reagent performs within the specifications

established by the laboratory for the test procedure. Documentation of concurrent testing

of reagents or acceptable quality control results will satisfy this requirement.

When the laboratory uses a manufacturer’s kit, the reagents of the kit must not be

combined, mixed, or replaced with components of another kit from a different lot

number, unless otherwise permitted and specified by the manufacturer in the package

insert. Use D5419.

Laboratories which use automated staining methodologies must follow the

manufacturer’s instructions. Use D5411.

Flow Cytometry

Staining controls for cell surface immunophenotyping by flow cytometry should consist

of either normal, cultured, or abnormal cells known to be positive for selected standard

antigens and must verify the proper performance of reagents. Frozen or other preserved

cells may be used. A negative reagent control must be run for each test cell preparation,

and is to consist of monoclonal antibody(ies) of the same species and isotype or

equivalent. Negative reagent controls will consist of:

(a) For indirect stains, an irrelevant primary antibody and the same secondary

antibody(ies) conjugated with the same fluorochrome(s) used in all relevant test

combinations; and

(b) For direct stains, an irrelevant antibody conjugated to the same fluorochrome and

at the same fluorochromes: protein ratio used in all relevant test combinations.

Probes §493.1273(a)

For flow cell cytometric surface immunophenotyping, is a negative reagent control used

to define a threshold for positive staining cells? If not, how does the laboratory define

the threshold for positive staining cells?

Is a quality control slide with the appropriate differential or special stain tested at the

same time patient specimens are tested?