Quality Management

An announcement of a new product available from Westgard QC:

• QC Validator Automatic QC Selection Engine
• Proprietary Technology
• Cost-effective QC is now practical
• Automatic QC is now possible
• Contact Information

Recommendations for "planning a statistical quality control procedure" can be found in the recent revision of NCCLS C24A2: Statistical Quality Control for Quantitative Measurements: Principles and Definitions; Approved Guideline - Second Edition, 1999, which is available from NCCLS (940 West Valley Road, Suite 1400, Wayne, PA 19087 - phone 610-688-0100).

Most of our support for QC planning has focused on providing tools and technology for the laboratory user, such as:

• OPSpecs Manual - Expanded Edition, which provides a workbook of OPSpecs charts for common control rules with 2 to 6 control measurement per run and for the full range of the CLIA "analytical total error" criteria for acceptable performance.This is no longer available.
  
• Normalized OPSpecs Calculator, which is an Internet tool that makes it easy to utilize a normalized form of the OPSpecs charts.
• EZ Rules 3 computer program, which can prepare OPSpecs charts for both analytical (allowable total error) and clinical quality requirements (a medically important change or "clinical decision interval").

These are "off-line" approaches and have not been integrated into existing instrument software, laboratory information systems, or computer workstations. For manufacturers, there would be obvious advantages to an "online" approach that could be made available within existing software.

QC Validator/EZ Rules 3 Automatic QC Selection Engine

We recently demonstrated the feasibility of embedding our QC Validator technology in other software. This is accomplished by providing our software engine as a DLL (dynamic link library) that can be accessed by any Windows program. The engine functions are as follows:

• Input parameters - number of control materials to be analyzed, quality requirement for the test, observed imprecision of the method, observed inaccuracy of the method, expected instability of the method - are provided by adding a single screen to the manufacturer's existing software.
• Control rules and the total number of control measurements are selected by the engine using our OPSpecs methodology.
• With information about the coding of control rules in existing software, the engine can return the control rules in the proper format for immediate implementation.

The behavior of this engine can be customized to fit the control rules available in the existing QC software, the QC practices prevailing in a geographical area, and the type of quality requirement preferred in a given marketplace.

Proprietary technology

The technology for the automatic rule selection engine is described in United States Patent 5,937,364 "Automatic selection of statistical quality control procedures," which was issued August 10, 1999. We would be happy to supply manufacturers with a copy of the patent, which can also be accessed at the website of the US Patent and Trademark Office: http://www.uspto.gov/patft/index.html. [Search for "westgard" in the 1998-99 database.]

The key scientific publications that describe this technology are the following:

• Westgard JO, Stein B, Westgard SA, Kennedy R. QC Validator 2.0: a computer program for automatic selection of statistical QC procedures for applications in healthcare laboratories. Comput. Methods Programs Biomed. 1997;53:175-186.
• Westgard JO, Stein B. Automated selection of statistical quality-control procedures to assure meeting clinical or analytical quality requirements. Clin Chem 1997;43:400-403.

Cost-effective QC is now practical

The development of the QC Validator automatic rule selection engine makes it much easier and faster to improve existing QC software. With careful selection of control rules and the number of control measurements, the cost-effectiveness of laboratory testing processes can be optimized by:

• Reducing false rejections and preventing wasteful repeat analyses;
• Reducing the number of control measurements to the minimum necessary to assure the desired quality is achieving;
• Maximizing error detection when necessary by use of multirule control procedures and the appropriate number of control measurements;
• Simplifying QC procedures when possible by use of single rule control procedures having low false rejection rates.

Automatic QC is now possible

The availability of the automatic rule selection engine also makes it possible to develop a totally automatic QC process in which:

• The user only needs to define the quality needed;
• The instrument selects the necessary QC procedure (control rules and N);
• The instrument provides ongoing estimates of imprecision and inaccuracy;
• The QC procedure adjusts automatically when method performance changes, relaxing when performance improves and tightening up when performance deteriorates - see the recent discussion QC 2000 that appears on this website.

Contact Information

For further information about the QC Validator / EZ Rules 3 automatic rule selection engine and currently available licencing/distribution arrangements, Westgard QC can be reached in the following ways:

Phone: 608-833-4718
Fax: 608-833-0640
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.