CMS SOM App. C, Tag D5431

(a)(2) Function checks as defined by the manufacturer and with at least the

frequency specified by the manufacturer. Function checks must be within the

manufacturer’s established limits before patient testing is conducted.

Interpretive Guidelines §493.1254(a)(2)

Function checks refer to those activities performed to evaluate critical operating

characteristics (e.g., stray light, zeroing, electrical levels, optical alignment, background

counts, counting efficiency) according to the accepted method of operation for each type

of device or instrument. Daily quality control activities and function checks are

performed prior to patient testing to ensure that an instrument is functioning correctly and

is properly calibrated (Checking electrical, mechanical, and operational functions may be

independent of the procedure). The performance of daily quality control activities may

serve as an additional instrument function check, since analysis of external control

samples check the operating characteristics of a test system, including instrument stability

and calibration.

The laboratory must follow and document the required functions checks as stated by the

laboratory information system (LIS) manufacturer for the LIS computer and devices such

as monitors, printers and modems.

For instruments that automatically perform function checks and flag problems, the

laboratory is required to document the corrective actions in response to the flagged

problems. Use D5793 for deficiencies related to documenting corrective actions in

response to the flagged problems.

Flow Cytometry:

A fluorescence standard(s) for each fluorochrome should be used each day of patient

testing to ensure:

• Proper alignment of the optical system;

• Standardization of the fluorescence detectors;

• Resolution of dimly-stained particles; and

• Appropriate compensation for spectral overlap of the fluorochromes.

Fluorescence standards should have the same fluorochromes as are used for the test, and

with the exception of alignment standards, should have similar fluorescence intensities as

found in the test specimens. The laboratory must have an acceptable range of

performance for all procedures.

Probes §493.1254(a)(2)

For those methods in which the centrifugation is a critical portion of the test, does the

laboratory check the RPM’s and timing periodically (e.g., urine sediments)?

Do the records of a laboratory that moves from testing site to testing site demonstrate the

performance of function checks as necessary?

In immunofluorescent test procedures, how does the laboratory ensure that the bulb is

emitting ultraviolet light at the correct wavelength?

How does the laboratory ensure that the fluorescent light source has not exceeded the

manufacturer’s established optimal timeframe?

For procedures or test systems that require pipetting or dilution of patient specimens

separately from controls or calibrators, how are autodiluters, microdiluters, and/or

pipettors checked for adequate and consistent delivery?

For those systems that perform simultaneous fluid delivery to multi-well plates or tubes,

how does the laboratory ensure uniform delivery of reagents or washing solutions to all

wells or tubes?

§493.1254 Standard: Maintenance and function checks.

(b) Equipment, instruments, or test systems developed in-house, commercially

available and modified by the laboratory, or maintenance and function check

protocols are not provided by the manufacturer. The laboratory must do the

following:

Interpretive Guidelines §493.1254(b)

The laboratory must establish and follow procedures for performing maintenance and

function checks on each piece of equipment/instrument it uses, including those that are

peripherally involved in patient testing (e.g., incubators, centrifuges, safety cabinets,

autoclaves and microscopes).

A manufacturer’s instructions may not require maintenance and function checks.

However, if the laboratory determines that a maintenance and/or function check protocol

is necessary in order to ensure accurate and reliable test results, the laboratory must

establish a maintenance and/or function check protocol and perform and document the

described activities as they are carried out over time.