Clinical Microbiology: Diagnostic Standards of Care

---

In addition to accrediting requirements, a number of nonregulatory guidelines and standards have been developed. Use of these guidelines and standards is, for the most part, voluntary, although some of the guidelines have been adopted by accrediting organizations as part of their accreditation requirements. Introduction of new tests or devices in clinical laboratories requires a robust process to determine that the tests or devices exhibit the same performance characteristics established by manufacturers as part of obtaining clearance or approval from the US Food and Drug Administration to market them in the United States.

There was a problem providing the content you requested

What is often unrecognized, however, is that commercial tests and devices exhibit substantial variation in performance characteristics in different settings. There are a number of reasons for this: All of these factors affect how laboratory tests perform; thus, tests and devices must be evaluated before they are used in clinical settings [ 28 ].

The terminology used to describe the process of introducing new tests remains somewhat inconsistent, with only subtle differences between some of the definitions. Some of the steps for implementation and validation of new tests are shown in table 2.

The time required to implement and validate a new laboratory test is substantial: Additional steps are needed to validate antimicrobial susceptibility testing before it can be used to monitor drug resistance routinely [ 29 ]. The introduction of new antimicrobial agents into clinical practice eventually necessitates antimicrobial susceptibility testing to monitor the development of resistance to those agents. The need for antimicrobial susceptibility testing varies: There is little need for most laboratories to test isolates for resistance to new antimicrobial agents until resistance has been reported in the literature.

Although it might be argued that resistance will go undetected unless antimicrobial susceptibility test results are obtained frequently and widely, not every laboratory needs to do this: In clinical microbiology laboratories, a large number of media and procedures may be used to generate just a single test result. For example, a routine wound culture includes a direct smear and a Gram stain, use of different aerobic and anaerobic media, possible use of fungal or mycobacterial media, Gram stains of bacterial isolates recovered in culture to guide identification procedures, necessary tests used for rapid or preliminary identification, tests used for confirmatory identification, antimicrobial susceptibility tests, and storage of isolates.

Each type of medium used, each individual test and procedure, and even the reporting of results must undergo QC on a regular basis.

Field Epidemiology Manual

The frequency and type of QC varies by the type of test, medium, or reagent. For some tests, QC must be performed along with every test. For other tests, QC must be performed only when a new lot number is to be used. For automated assays, QC is often performed daily but is typically much more extensive than that used with manual tests. Some instruments require multiple QC tests, calibration of the instrument, and establishment that the linearity of the instrument remains stable from day to day.

Although QC results are not displayed along with test results—and, therefore, are not apparent to health care providers who order cultures or review results—infectious diseases specialists should be aware of the extent and complexity of QC used in microbiology laboratories. Such awareness aids the understanding of the time required to report test results, explains delays in reporting results i.

Even basic systems that only have the capability for computer-based order entry can improve patient care by providing standardized order sets, minimizing errors related to handwriting, eliminating use of ambiguous abbreviations, facilitating resolution of discrepant or redundant orders, and improving the ability of laboratories to report critical values. Use of a CPOE system also substantially improves the timeliness and quality of audits. The greatest improvement in quality of care and patient safety should occur with CPOE systems that are fully integrated with other information systems, in which the available information is processed by an intelligent software system.

For example, an order for an antimicrobial agent would be screened by the software for results of microbiologic cultures, antimicrobial susceptibility testing, drug levels, physiologic parameters e. Components of such systems exist in many hospitals, but overall integration remains uncommon. The potential benefit of such systems obviously requires accurate and up-to-date information. For microbiology laboratories, this will be a challenge, because of the time required to isolate and identify pathogenic microorganisms, the multiplicity of methods used for these procedures, and the complex nature of result reporting i.

Indeed, much of the information developed as part of diagnostic microbiology is not amenable to such a system—for example, information from cultures that are in progress, efforts to isolate pathogenic microorganisms from other contaminating flora, slow growth of some microorganisms, equivocal microbial identification results, and the need for temporary descriptions of many microorganisms e. It is apparent that a number of issues need to be addressed for CPOE systems to make full use of information from clinical microbiology laboratories.

The role of antimicrobial susceptibility tests to guide empirical therapy, to refine therapy once pathogens have been isolated and identified, and to detect new types of antimicrobial resistance is well established. Other roles of antimicrobial susceptibility testing for patient care, such as development of cumulative antibiograms, creation of antimicrobial formularies, and detection of new antimicrobial resistance strains or trends, are also well established.

What may not be apparent to most providers is that generating accurate and reproducible antimicrobial susceptibility test data requires perhaps the most extensive QC program used in clinical laboratories today. These guidelines are extensive and require rigorous adherence to each step of testing for results to be accurate and reproducible.

Specific guidelines have been developed not only for different categories of bacteria and fungi e. Perhaps the most important guidelines published by CLSI are that antimicrobial agents should be tested against different microbial pathogens. The information used to develop these guidelines is based on clinical, pharmacologic, and microbiologic data. It is strongly recommended that clinical microbiology laboratories and providers both adhere to these guidelines; testing antimicrobial agent-pathogen combinations that are not recommended may generate antimicrobial susceptibility test results that either are misleading or cannot be interpreted.

In general, it is also strongly recommended that new antimicrobial agents should not be tested in clinical laboratories until there are sufficient data for CLSI guidelines to be developed and published.

The CLSI also publishes guidelines for the development of cumulative antibiograms [ 31 ]. When developed and interpreted correctly, these documents provide the data needed to guide empirical antimicrobial therapy as well as provide a basis for developing and modifying formularies.

To ensure that the data are accurate, a number of definitions and criteria must be defined before creating antibiograms.

These include the following: If a clinical microbiology laboratory has sufficient software and resources available, it would be ideal to develop antibiograms that are specific to units—particularly intensive care units— provided that adequate numbers of isolates are available for analysis and to update antibiograms frequently.

Some commercial laboratory information systems include software for developing antibiograms, and some commercial antimicrobial susceptibility testing systems provide similar capability. Detection of new types or patterns of antimicrobial resistance may be fortuitous or the result of active surveillance. The former should not be used to guide patient care until the data are confirmed by a reference method; published reports of new types or patterns of resistance typically reflect extensive confirmatory testing.

Because most microbiology laboratories use commercial systems for antimicrobial susceptibility testing, which may or may not yet have the capability of detecting newer forms of resistance, reliable means of detecting new types or patterns of antimicrobial resistance often lag behind published information.

Amazon Giveaway allows you to run promotional giveaways in order to create buzz, reward your audience, and attract new followers and customers. Learn more about Amazon Giveaway. Diagnostic Standards of Care. Set up a giveaway. Pages with related products. See and discover other items: There's a problem loading this menu right now. Learn more about Amazon Prime.

Get fast, free shipping with Amazon Prime. Get to Know Us. English Choose a language for shopping. Explore the Home Gift Guide. Amazon Music Stream millions of songs. Amazon Advertising Find, attract, and engage customers. Amazon Drive Cloud storage from Amazon. Estimating Odds Ratios in the presence of interaction Fitting logistic regression models Interpreting model coefficients Linear models Model building strategies The logistic model Wikis - Links Share this View history Article Articles - Wiki Subscribe Article History You are viewing the most recent version of this page.

An expert reviewed version of this page does not yet exist. Clinical role of the microbiology laboratory. Articles - Wiki Rate This 1. The microbiological processing of patient specimens and serodiagnostic analyses are fundamental to the everyday diagnosis, treatment and management of patients with infectious diseases.

However, it is still wise to also process specimens to confirm the diagnosis and the specific implicated pathogen, as well determining its antimicrobial susceptibility pattern antibiogram. There are also some non-microbiological tests e. More vulnerable patients e. These are far more challenging than, for example, those taken for haematological or clinical chemistry investigations and careful attention needs to be paid to them, not least because it is often impossible to re-collect them.

The second major issue is that microorganisms are living organisms and, if good specimen submission management is not in place, it can result in serious issues, such as false positive or negative laboratory results. These can arise if, for example, infecting microorganisms are allowed:. The latter is a particular issue because, as we have already pointed out, such commensals can also cause infections especially HAIs.

FEM - Clinical role of the microbiology laboratory.

However, before declining these, the laboratory must communicate with the clinician in charge. For example, a wound swab sent for culture requesting a search for anaerobic bacteria, but unfortunately sent without insertion of the swab into an appropriate transport medium, should not be cultured as such organisms are unlikely to still be viable.

Laboratory Accreditation

If the specimen is unrepeatable then culture should be agreed and the report covered with the appropriate caveats. Laboratories should be accredited for all of their services.

Editorial Reviews

To do this there should be appropriate standard operating procedures SOPs in place to validate all of their work, including the specimen processing and correct interpretation of any results. SOPs should also extend to correct specimen selection, collection and transport and these should be agreed between the clinicians, clinical laboratory personnel and hospital management. It would include consideration of any equipment e. These systems should be audited regularly and any issues which arise addressed; records of this should be available for accreditation bodies.

Here is not the place to cover this in any depth, but it is essential to be able to prove the quality of the results of every microbiology laboratory. All the necessary steps should be taken to ensure quality assurance i. The laboratory should save all specimens until the result is finalised.

• Beginning Contract Law (Beginning the Law)
• How To Train A Puppy
• mugennokanousei (Japanese Edition)
• The Ninety Trillion Fausts (Quintara Marathon Book 3)
• Strange erotic fantasies By Luise Nina |110 pages of pure eroticism | 6 new erotic stories