National Committee for Clinical Laboratory Standards NCCLS

Procedures should be organized and indexed in the form of manuals and must be written in compliance with National Committee for Clinical Laboratory Standards (NCCLS) GP2-A2 (3). Technical procedures designed for use at the bench should be complete, easy to follow, and readily available to testing personnel. These procedures must contain the following information for each assay performed ... 

The degree of resistance of the mutant clones to the relevant PRP may be assayed by a number of methods. The broth microdiluition susceptibility test, a reference method for determination of the Minimum Inhibitory Concentration (MIC), may be performed according to the guidelines of the National Committee for Clinical Laboratory Standard (NCCLS) as described (20). An example of the increase in the MIC values for Bac7(l-35) in mutagenized HB101 is shown in Table 1. Another suitable and simple method, here described, is the count of bacterial viable cells after incubation with the peptide. 

Standardized methods for surveillance of antifungal drug susceptibility have been a recent development (Rex et al, 1993). The M27 protocol of the National Committee for Clinical Laboratory Standards (NCCLS) for testing of yeasts focused on laboratory to laboratory reproducibility and became an approved standard in 1997 (National Committee for Clinical Laboratory Standards, 1997). A modification of M27 for testing of molds has recently been proposed as NCCLS document M38-P (National Committee for Clinical Laboratory Standards, 1998). With these tools, collaborative studies to validate the predictive power of these results have been possible. Interpretive breakpoints for... 

The hierarchy established among the different methods and materials suggests an easy organization (Tietz, 1979). However, serious practical problems have hampered fast progress. In the United States and in Europe, the National Committee for Clinical Laboratory Standards (NCCLS) and the European Committee for Clinical Laboratory Standards (ECCLS) have been founded. These standardization organizations promote the development and the ultimate use of reference materials and methods. The National Bureau of Standards (NBS) and the Centers for Disease Control (CDC) in the United States (Bayse, 1982), and the European Community Bureau of Beference (BCR) in Europe, undertake projects oriented more toward the preparation of certified reference materials (BCR, 1982). 

To resolve such confusion, several professional organizations have recommended water quality standards that are graduated according to classes of use. These specifications enable users to define their needs with more precision. Typical are those of the ASTM, the National Committee for Clinical Laboratory Standards (NCCLS), the College of American Pathologists (CAP), and the American Chemical Society (ACS). These specifications are summarized in Table 6-6. In general, laboratory water quality is defined in terms of its resistivity. The historical focus on resistivity as a measure of water quality presupposes that dissolved minerals are the main concern. Often it is true, but resistivity has been used as the major yardstick for water purity mainly because it has been the most easily measured. 

Regularly updated guidelines have been provided by the National Committee for Clinical Laboratory Standards (NCCLS) and are widely used in many countries, although the British Society for Antimicrobial Chemotherapy has produced its own guidelines and testing procedures (see Further reading section). 

The development of TLA and modular automation required the development of computer systems known as laboratory automation systems (LAS) with extensive software to support these systems in the clinical laboratory. For a more detailed description of the relationships between an LAS, LIS, automation equipment, and laboratory analyzers, the reader is referred to the National Committee for Clinical Laboratory Standards (NCCLS) standard on laboratory automation communications. ... 

National Committee for Clinical Laboratory Standards (NCCLS). Prehminary evaluation of quantitative clinical laboratory methods, approved guideline-second edition. NCCLS document EP10-A2. Wayne, PA NCCLS, 2002. 

The connectivity standard was approved by the National Committee for Clinical Laboratory Standards (NCCLS) in 2001 as the POCT 1-A standard. Essentially, if a POCT device incorporates this standard, it should easily be able to communicate with laboratory and hospital information management systems, allowing exchange of data and infor-... 

Method evaluation in the clinical laboratory is influenced strongly by guidehnes. The National Committee for Clinical Laboratory Standards (NCCLS) has published a series of consensus protocols for clinical chemistry laboratories and manufacturers to follow when evaluating methods (see the NCCLS website http //nccls.org). The International Organization for Standardization (ISO) has also developed several documents related to method evaluation.In addition, meeting laboratory accreditation requirements has become an important aspect in the method selection and/or evaluation process. In recent years, accrediting agencies have placed increased focus on the importance of total quality... 

The comprehensive nature of quality assurance programs and their missions, goals, and activities have been discussed in greater detail by Filers. There are also detailed outlines of the elements of cost management for quality assur-ance " detailed recommendations by professional organizations, such as the College of American Pathologists (CAP), the National Committee for Clinical Laboratory Standards (NCCLS), " and the International Federation of Clinical Chemistry and books devoted to quality assurance practices in clinical laboratories. 

Atomic Absorption Spectrometry Methods The National Committee for Clinical Laboratory Standards (NCCLS) has approved a method using atomic absorption spectrophotometry (AAS) as a reference method for measuring total serum calcium. This method has been compared with isotope dilution-mass spectrometry (ID-MS), the definitive method for total serum calcium developed by the National Institute of Standards and Technology. The reference method is reported to have an accuracy of 100 2%, compared with 100 0.2% for ID-MS. Although AAS can provide better accuracy and precision for total serum calcium than the widely used photometric methods, it is used by only a few laboratories. It should continue to be used for validating new total calcium methods. 

For quantitative methods, the ICH guidelines recommend validating a range that extends 20% below the lower end of the range and 20% above the upper end of the range (for content uniformity the range is extended to 70-130% of the SOP range). For the linearity portion of the method. National Committee for Clinical Laboratory Standards [NCCLS (9)] recommends at... 

Most antimicrobial susceptibility tests used in the clinical laboratory are well characterized and have been standardized by the National Committee for Clinical Laboratory Standards (NCCLS). However, controversies still exist surrounding the exact test methods, interpretation and reporting of test results, and application of the results to the treatment of patients. Nevertheless, there are many investigations that show that the general antimicrobial susceptibility or resistance profile of an infecting organism correlates with clinical and/or microbiologic responses to therapy. 

Many, if not all, of these procedures have evolved over many years and with continuous feedback within the scientific communities around the world. Much of this has been conducted within an organization called the Clinical Laboratory Standards Institute (CLSI) formerly known as the National Committee for Clinical Laboratory Standards (NCCLS). Many guidance documents are available from this organization s Web site (see below) that explain how some of the assay performance characteristics are established for the purposes of diagnostics. A number of these experiments are very similar to, or indeed the same as, experiments we conduct in validating biomarker assays for use in drug development and are listed in Table 7.1. 

For antimicrobial assays, there are several common methods employed. Due to its ease of operation, the most common method used is the disk diffusion method, which involves the application of a material onto a filter paper disk, and then the disk is placed onto solid medium previously seeded with the test microorganism of interest. Sometimes, the sample is dissolved in an appropriate solvent before application onto the paper disk. This method is very common in the evaluation of antibiotics and is the method adopted by the National Committee for Clinical Laboratory Standards (NCCLS). The method depends on the aqueous solubility of the antibiotics in order to facilitate diffusion through the solid medium. Essentials oils, however, are generally hydrophobic, do not readily diffuse through an aqueous medium and, therefore, the prevalence of false negatives or reduced activity might then be anticipated. 

The general test criteria describe in vitro testing requirements for the antiseptic ingredient, the vehicle, and the final formulation. The proposed testing methods of Minimum Inhibitory Concentration study are described in the National Committee for Clinical Laboratory Standards (NCCLS) Manual M7, and the American Society for Microbiology time-kill study [2]. Researchers are encouraged to submit alternative test methods for approval. 

Bauer, A. W., M. M. Kirby, J.C. Sherris and M. Turck. 1966. Antibiotic susceptibility and testing by a standardized single disc method. Am. J. Clin. Pathol. 45 493-496.) New feature numbers have been added to reflect the changes and additions as published by the National Committee for Clinical Laboratory Standards (NCCLS). (See Performance Standards for Antimicrobial Disc Susceptibility Tests. Second edition May, 1981 NCCLS, Vol. 1 No. 6 771 E. Lancaster Avenue Villanova, PA 19805.) (See also Thornsberry, C. 1980. Disc agar diffusion susceptibility test. 

Atomic absorption spectroscopy is a preferred method in clinical chemistry. However, UV/Vis spectrometry by use of chelating methods combined with photometry of chromophores offers simple and fast approaches. Examples are methods recommended by the National Committee for Clinical Laboratory Standards (NCCLS 1990) taking ferrocene for Fe, eliminating interferences by Cu by addition of thiourea. Mg is determined by addition of xylidyl blue, Ca by use of o-cresolphthalein or arsenazo complexes. Interferences by Mg are reduced by addition of 8-hydroxyquinoline. Further chromophores and complexing agents are discussed in subsequent chapters and elsewhere [39]. 

Antimicrobial susceptibility testing - 3rd Edition. Standards Institute (National Committee for Clinical Laboratory Standards-NCCLS). Villanova, PA, 1990... 

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