Quality control in the new environment: microbiology.

Quality control in the new environment: Microbiology Microbiology quality assurance programs are in a transition period. Up to now, the focus has been on surveillance of laboratory procedures. In the next decade, QA programs will broaden to include the entire process from a physician's test order to interpretation of laboratory results.

Two major factors will fuel this change. First, the national emphasis on control of health care costs is causing a reevaluation of test ordering practices as well as elmination of nonproductive QA procedures. Second, new rapid testing and data communcation technologies will enable the microbiology laboratory to contribute to the initial management of the patient with an infectious diseas. The laboratory will assume a greater role in elimination of unnecessary test requests and in interpretive reporting.

At the same time, quality control measures in the laboratory will continue to come under close scrutiny. Due to the lack of quality control data when the Clinical Laboratory Improvement Act was passed in 1967, QC measures covering all aspects of lab testing were implemented. The systematic collection of data since then has demonstrated that some methods used for QC of microbiology materials, equipment, and test procedures are both unnecessary and costly. In addition, the quality of commercially prepared microbiological products--including media, reagents, and test systems--has improved significantly and requires less QC by the user.

These trends and a generally recognized need for revised quality control standards led various inspection agencies to modify their guidelines and prompted the National Committee for Clinical Laboratory Standards to write a quality control standard for commercially prepared media.

Recent data suggest that necessary quality control measures vary with the size and type of laboratories allocate a larger percentage of their resources to the quality control of test procedures. This probably reflects the low number of requests such labs receive for most tests, since infrequently performed procedures require QC testing with each use. It is a problem that may have a significant impact on the growth of physicians' office labs, where most tests are performed infrequently. There is cleraly a need to better define appropriate quality control standards for laboratories of different sizes.

The national pressure to reduce health care costs has had a dual impact on laboratory quality assurance programs. Individual labs are assessing the value of current quality control methods and eliminating nonproductive procedures. In general, monitoring personnel functions and equipment is the most effective approach; quality contol procedures for monitoring media and reagents are the least effective.

The pressure for laboratory cost containment is resulting in consoldiation of services within a geographic area via the development of regional reference laboratories. The resulting higher test volume should allow a reduction in resources committed to QC.

However, the regional reference lab must employ innovative techniques to overcome problems that arise from physical separation of the laboratory and the clinican: a lack of communcation between the lab and the doctor, potentially long turnaround times, and difficulty maintaining specimen integrity during transport.

Information transfer systems pose a major challenge to microbiology laboratories in the delivery of accurate and reliable data. The hospital computer and other technological advances have given these labs the opportunity to generate preliminary reports that can influence the initial management of a patient and to provide interpretive reporting. The challenge will be to insure the accuracy and clinical utility of this rapidly reported information.

Although achieving consistent and reliable laboratory tests is one goal of a microbiology QA program, there is no practical method to insure that every result will be accurate. The success of any quality assurance program relies on performance testing and communciation among those performing the tests, the laboratory director, and the clinical staff. The laboratory must receive continuous feedback on the accuracy and clinical utility of its data, and the clinical staff must receive feedback on specimen quality and test interpretation.

The first step in developing and implementing a QA program is to assign the administrative responsibilities to one individual. This person is in charge of overall program operation and may delegate responsibility for various elements to others. Administrative responsibilities include accurate and consistent recording of quality control results, prompt review of QC results for problems, troubleshooting, and timely review of these activities with the appropriate laboratory and clinical staff members.

Pratical procedures and well-trained personnel are the most important features of a QA program. Once the program is operational, all personnel should understand the need for quality control procedures and actively participate.

Clear definition of the program's elements is essential. These elements include specimen quality, extent of speciment processing, quality control of laboratory performance, personnel performance, and methods to measure quality assurance. We will examine each in turn.

* Specimen quality. The first priority in any QA program is submission of an appropriate specimen. The microbiologist has to instruct the medical staff about proper collection and transportation of clinical specimens and insure that these procedures are followed. This requires ongoing educational dialog between the lab and specimen collectors.

Quality/cost/clinical relevance relationships in microbiological testing having come in for considerable discussion. In light of prospective payment and the growing popularity of health maintenance organizations, quality assurance programs are necessarily focusing on elimination of unnecessary testing. Thus developing test-ordering criteria will become an integral part of the microbiology laboratory's QA programs. Access to the patient's clinical records through the laboratory computer will permit a review of many requests before testing begins.

Finally, microscopic techniques are available for specimen evaluation prior to culture. For example, the presence of numerous squamous epithelial cells indicates contamination by oropharyngeal secretions for lower respiratory tract specimens and superficial contamination of wound, middle ear, and endometrial specimens.

Some speciments--such as Foley catheter tips, colostomy drainage, vomitus, and lochia--are not useful for diagnosing infections and should not be cultured. Microbiologists should actively seek new screening methods for assessing specimen quality and critically review the clinical utility of existing procedures.

* Extent of specimen processing. Microbiologists are responsible for developing and implementing a systematic program to limit processing done on specimens of questionable clinical relevance while concentrating laboratory resources on specimens and procedures that produce clinically useful information. The former effort shouild be directed toward specimens that the normally contaminated with indignous flora and thos that yield multiple isolates of questionable clinical relevance.

It is difficult, if not impossible, to decide what is significant without information on the patient's immune status or underlying disease. For this reason, good communication with the medical staff is needed. Rigidly adhering to protocol without considering all circumstances may raise costs through repeat testing and increased length of stay, and could also have serious medical consequences. A highly competent staff is the pivotal factor--well-trained individuals who understand the complexities of pathogen-host interaction.

* Quality control of lab performance. Microbiology QC essentially involves surveillance procedures to insure the reliability, accuracy, and consistency of all tests and equipment. Specific performance criteria for evaluation of laboratory tests are readily available.

Procedure manual. The procedure manual, a reference for standardization and organization of all tests and functions, is the most important document in the microbiology laboratory. It is written primarily for new r inexperienced personnel but also serves as a reference for experienced technologists.

The manual should contain sections on specimen collection and transportation, specimen acceptability and criteria for rejec tion, procedures for processing specimens, systematic descriptions of the tests performed, QC methods and preventive maintenance, safety, result reporting, and key references. It should try to address common problems and problems unique to a particular lab.

Reagents and stains. Labeling on reagents and stains should show the contents, concentration, date prepared or received, date opened, and the expiration date. An inventory list or reagent file should also detail appropriate storage conditions. Manufacturers are required to place an expiration date on most materials. New lots of reagents should be tested with positive and negative control organisms upon receipt or before they are used.

The frequency of additional surveillance testing is discussed by several authors. Follow the manufacturer's quality control recommendations with commercial kits.

Media. The micrbiology laboratory is responsible for insuring that all media are sterile and will perform as intended, whether prepared in the laboratory or purchased. for laboratory-made media, detailed records must be kept of components, lot numbers, pH, sterility testing, and the results of performance testing with stock organisms of each type of medium.

Perofrmance testing should include assessment of the medium's ability to support growth, its inhibitory and selective properties, and biochemical reactions. The stock organism tested against a specific medium and the stability and method of storage for each medium are listed elsewhere.

For commercially prepared media, the laboratory may choose to accept the manufacturer's quality control results instead of repeating the tests. The manufacturer must provide documentation of 1) the methods used, 2) criteria for acceptable performance, and 3) acceptable media performance. The prudent laboratory initially confirms the manufacturer's results and requests information on the environmental conditions during media transport.

New standards for quality control testing of commercial media will be written by the appropriate accreditation agencies as data are collected and evaluated.

Antimicrobial susceptibility testing. Testing of clinical isolates for antimicrobial suscptibility has become an important aid in selecting the appropriate drug to treat infection. Depending on the particular susceptibility test used, several factors can influence results: inoculum size; antimicrobial stability; incubation atmosphere, time, and temperature; medium; pH; depth and concentration of agar; and the antimicrobial agent's diffusion characteristics. Probably the most important variable in susceptibility testing involves human error in interpreting results.

The NCCLS has modified its standard for disk diffusion susceptibility testing with respect to frequency of quality control testing. After a laboratroy establishes satisfactory test performance through daily monitoring, the frequency may be decreased to weekly surveillance with each control strain. When the results are unacceptable, daily testing should be done until the source of the error can be identified.

QC tests should also be performed before use of new lots of media or antimicrobial disks. The QC procedures for other susceptibility tests are described in the literature.

Equipment. Surveillance testing of laboratory equipment depends on adherence to a preventive maintenance schedule and periodic performance checks. The temperature of inclubators, refrigerators, freezers, water baths, and heating blocks should be monitored each day of use. The carbon dioxide concentration in capneic incubators should be maintained between 5 and 10 per cent and measured with an acceptable method (i.e., Fyrite indicator or CO.sub.2 monitor). Performance tolerances and frequency of surveillance should be established for all equipment.

A well-designed QC program for laboratory equipment is essential for producing accurate and reliable results. It can also decrease repair costs prevent interruptions in wokr flow, and minimize the need for backup equipment.

Reference laboratories. All microbiology laboratories should use a good refernece laboratory. Smaller labs need if for infrequently requested specialized procedures. Since it is usually not cost-effective to perform these tests on a limited basis, in-house expertise never develops. A reference laboratory can also serve as a consultant on problems and as a source for stock organisms or unknown samples. Larger labroatories can use the facility to confirm results or for comparison in evaluating different test methods.

* Personnel performance. Before new staff members begin reporting out results, the should receive appropriate and thorough training in all aspects of the microbiology laboratory, under the direction of a lead technologist. Part of this training is mandatory familiarization with the procedure manual, which all personnel should regularly review.

The laboratory should establish a continuing education program and encourage staff members to attend meetings and keep up with the literature. A communication system should also be set up for the staff, supervisor, and director; it might take the form of weekly meetings or daily lab rounds.

Each employee's productivity should be monitred to insure that it is neither too high (indicating a low standard of quality) nor too low (suggesting an inefficient operation).

* Measuring quality assurance. It is difficult to measure the overall quality of a microbiology laboratory. The initial step--after implementing a quality assurance program--is to promptly review results of the various surveillance efforts. This review should indicate whether the laboratory has frequent difficulties or a sporadic problem that may or may not be clinically significant.

Since many problems are personnel-related, it is important to establish a method to review the work performed. This may include checking worl cards for adherence to procedures; reviewing unusual results for consistency with the clinical situation; or comparing common susceptibility profiles with individual strains for aberrant results. The most important thing is to actively monitor work in progress through frequent laboratory rounds and spot checks.

Using internal blind unknowns is an effective way to measure the overall performance of the entire laboratory system. Unknowns can be simulated or real specimens, submitted under the name of a deceased patient or as an autopsy specimen. For serological procedures, the original specimen can be saved and resulbmitted. The frequency of testing unknowns can be adjusted to the needs of individual laboratories.

Technologists should also test external unknowns submitted by an inspection agency--such as the College of Americal Pathologists, the Centers for Disease Control, or a state health laboratory--or by some other laboratory, such as a county health department or reference labl.

Since passage of the Clinical Laboratory Improvement Act in 1967, it has been demonstrated that quality control is an essential component of quality health care. With the increased pressure to reduce health care costs, the emergence of new technologies, and rapid information transfer, the microbiology laboratory must become more involved in an expanded quality assurance program that begins with test ordering and ends with the clinician's interpretation of test results. This approach requires the combined efforts of all members of the health care team.