Q and A

December 2007
Originally published in CAP TODAY

Ed Finkel

From the files of the CAP’s checklist-related questions. Answers reviewed by Stephen J. Sarewitz, MD, chair of the Checklists Committee and staff pathologist, Valley Medical Center, Renton, Wash.

Q: What are the CAP's quality control requirements for the new molecular systems to detect methicillin-resistant Staphylococcus aureus, or MRSA?

A: The most recent revision to microbiology checklist question MIC.63262, phase II, addresses quality control. The checklist item reads:

Are controls run daily for quantitative and qualitative tests?

Controls should verify assay performance at relevant clinical decision points. Controls must be run at least as frequently as recommended by the manufacturer.

Note 1: Except for tests meeting the criteria in Note 2, below, external surrogate sample* controls must be run as follows:

a. For quantitative tests, 2 controls at 2 different concentrations must be run daily.

b. For qualitative tests, a positive and negative control must be run daily.

Control testing is not necessary on days when patient testing is not performed.

Note 2: Daily controls may be limited to built-in/electronic/procedural (e.g., internal) controls for tests meeting all the following criteria:

1. For quantitative tests, the test system includes 2 levels of electronic/procedural/built-in internal controls that are run daily.

2. For qualitative tests, the test system includes a built-in/electronic/procedural control run daily.

3. The laboratory has performed and documented studies to validate the adequacy of limiting daily QC to the built-in/electronic/procedural controls. The validation protocol should be defined by the laboratory director.

4. External surrogate sample controls (as indicated in Note 1a and 1b, above) are run for each new lot number or shipment of test materials.** For qualitative tests, best practice is to also run a sensitivity control on new lots of reagents/test materials using a previously tested patient specimen or other external material. The sensitivity control is used to verify detection of low-level target sequences, e.g., pathogens or tumor markers.

*A "surrogate sample" is a specimen designed to simulate a patient sample for quality control purposes. For example, traditional external liquid control materials are considered surrogate external surrogate sample controls.

**Repetition of the initial validation study is not required when running external surrogate sample controls with new lots/shipments of test materials.

Q: Are references available about notifying doctors' offices about high-grade malignancy cases? We cannot find a requirement for this practice in the CAP checklists. I know CLIA requires laboratories to report malignancies and critical values, and we consider high grade to be similar to a critical value, so we contact the physician.

A: CLIA has no specific requirements about reporting malignant or premalignant diagnoses. There is a common misunderstanding about CLIA and CAP checklist requirements for communicating critical results. A critical result denotes that a condition is imminently life threatening. Most diagnoses of malignancy and premalignancy do not indicate that the conditions are imminently life threatening, so the conditions would not be considered critical values. However, reporting a malignancy appropriately is a CAP safety goal, as noted in laboratory general checklist item GEN.20365, phase II:

Does the laboratory address the current CAP Laboratory Patient Safety Goals?

Note: The current CAP Laboratory Patient Safety Goals are: 1) Improve patient and sample identification at specimen collection, analysis and resulting; 2) Improve verification and communication of life-threatening or life-altering information regarding malignancies, HIV (and other serious infectious diseases), cytogenetic abnormalities, and critical results; 3) Improve identification, communication, and correction of errors in a timely manner; 4) Improve the coordination of the laboratory's patient safety role within healthcare organizations. The laboratory must document that these goals have been addressed by evaluation and/or monitoring of the processes involved. Laboratory processes related to the Patient Safety Goals must be evaluated on an annual basis.

The reporting of a malignancy is also subject to anatomic pathology checklist question ANP.12175, phase I, on the reporting of unexpected or significant surgical pathology findings. The question reads:

Is there a policy regarding the timely communication, and documentation thereof, of significant or unexpected surgical pathology findings?

Note: Certain surgical pathology diagnoses may be considered particularly significant or unexpected. Such diagnoses may include: malignancy in an uncommon location or specimen type (e.g., hernia sac, intervertebral disk material, tonsil, etc.), absence of chorionic villi when clinically expected (potential ectopic pregnancy), change of a frozen section diagnosis after review of permanent sections, and/or mycobacterial, fungal, or other significant infectious organisms identified on special stains. Diagnoses to be defined as "significant" or "unexpected," if any, should be determined by the pathology department in cooperation with local clinical medical staff. Consideration should be given to assuring, with reasonable effort, prompt communication of such results by telephone, pager, or other system. There should be documentation of date and time of such special notification (which may be included in the pathology report or in laboratory files).

As you noted, the cytology checklist does not require the laboratory to notify submitting physicians about new diagnoses of high-grade squamous intraepithelial lesion, or HSIL, gynecologic cytology cases. A diagnosis of HSIL is not considered to be unexpected in most laboratories. It is up to the laboratory director to determine if such a diagnosis should be reported in a special manner.

Q: Do I have to vent the microwave oven if it is being used to warm slides or heat simple solutions and is being used in a negative pressure room?

A: Venting is only required for microwave devices being used for fixation, processing, or decalcification, in which volatile, potentially toxic solutions are being used. Venting is not required for staining procedures using nonvolatile, nontoxic reagents, such as iron staining. If volatile solvents are being processed in the microwave and you can smell the vapors in the room, the microwave device is not adequately vented.

In general, simply placing the microwave in a negative pressure room is not adequate-unless the unit were placed next to an exhaust vent and the solvents could not be detected by smell. Free-standing hoods, which are often used for small linear stainers, may eliminate the need for venting to the outside.

Anatomic pathology checklist question ANP.29430, phase I, addresses this question. It reads:

Are microwave devices properly vented?

Note: Microwave devices should be placed in an appropriate ventilation hood to contain airborne chemical contaminants and potentially infectious agents. Before operation of the microwave device, flammable and corrosive reagents should be removed from the hood to prevent fire or chemical damage to the electronic components of the device. Microwave devices used outside a fume hood should have an integral fume extractor that is certified by the manufacturer for use in a clinical laboratory.

The effectiveness of ventilation should be monitored at least annually.

This checklist question does not apply if only non-hazardous reagents (and non-infectious specimens) are used in the device (e.g., water, certain biological stains, paraffin sections). The laboratory should consult the MSDS sheets that are received with the material to determine proper handling requirements and safe use.