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Go read it!	Essay Title	Preview	Availability
	1999 Round-up		Public
	Method Validation course questions		Public, BMV
	FAQ's about Method Validation		Public, BMV
	1998 Round-up		Public
	FAQ's about Basic QC Practices		Public, BQC
	FAQ's about CLIA'88, JCAHO & CAP		Public, BQC
	Multirules and Validator; What's a run?		Public
	FAQ's about OPSpecs charts; Coag PT & PTT		Public
	FAQ's about Power Functions and Critical-Error Graphs		Public
	FAQ's about Multirule QC; Immunoassay QC		Public
	FAQ's about QC Validator		Public
	Using Mean and Range charts		Public

Using Mean and Range charts

How can I set up mean and range charts for a calcium method? Read the answers Back to Top

What is QC Validator?

How do you choose a decision level? Should the stable imprecision observed be matched to the decision level defined or should you use the average of the imprecision observed for the different control levels? Should the stable inaccuracy observed be matched to the decision level defined or should you use the average over the analytical range of interest? How is the frequency of errors determined? Is it necessary to run Validator for both the analytical and clinical quality requirements? Which graph is actually used to choose the control rule(s) & number of control measurements (N) ? Power function graphs? Critical-Error graphs? OPSpecs charts? What if you can't achieve 90% error detection with less than 5% false rejection? Read the answers Back to Top

FAQ's about multirule QC; Immunoassay QC

What is N? What's the best way to chart QC for multirule applications? Does the 12s warning rule have to be used in a computerized implementation? Can other rules be used as warning rules rather than rejection rules? Other than better error detection, are there any reasons to multirule procedures instead of single rules? What rules are most sensitive for detecting systematic errors? What causes systematic errors? What rules are most sensitive for detecting random error? What causes random errors? When can a single rule QC procedure be used instead of a multirule procedure? How do you decide if you need to apply rules across runs? When one rule in a multirule combination is violated, do you exclude just that control value from the QC statistics? When should you use the 41s and 10x rules for "warning" rules and when should you use them as out-of-control rules? Should I have an 12s rule violation for starting evaluation of violations of 41s, 10x, 8x and 12x rules? When would I use 8x and 12x rules? Immunoassay Questions: Are the manufacturer's specifications for acceptable control values too wide? Should we set our own control limits based on our control data? How do you use control charts on extremely stable immunoassay analyzers? How do you determine the frequency with which to run controls on extremely stable analyzers? Where can I find some example QC planning applications for immunoassay methods? Read the answers Back to Top

FAQ's about Power Function and Critical-Error Graphs

Why aren't actual concentration units used on the x-axis? Why is the y-axis given as probability instead of average run length (ARL)? Why aren't the power curves smooth? How good are the probabilities estimated by computer simulations? Why is a Ped of 0.90 considered to be ideal? Read the answers Back to Top

FAQ's about OPSpecs charts; Coag PT &PTT

Why isn't the x-axis labeled CV since imprecision is presented in percent? Why isn't the size error on the x-axis presented in units of concentration? Why is the y-axis labeled biastotl instead of biasmeas? What do TEa and DInt mean in the headings of the OPSpecs charts? How do I decide whether to use an analytical or clinical quality requirement? What is the meaning of the SE in the %AQA(SE) heading on an OPSpecs chart? What does %AQA mean? Why is 80% used instead of 90% AQA for the random error OPSpecs chart? Aren't 50% and 25% AQA too low to be useful? What's the meaning of the "maximum limits of a stable process" line? Is there any practical use for the "maximum limits" line? Coagulation PT & PTT Testing We use unassayed control materials for coagulation PT and PTT testing. Ranges must be established for each lot. Each time ranges are established, the limits are very tight, giving way too many QC outliers. What are your suggestions to help this? Read the answers Back to Top

Multirules and Validator; What's a Run?

How are the different levels of control incorporated in the power curves? How does the number of control materials affect automatic QC selection? How does the number of runs (R) affect the selection of control rules? What are the implications of R in the simulation of power curves and the application of rules in a multirule procedure? What rules are used across runs? Why is the R4s rule restricted to a single run? What about using the R4s across materials within a run? Does the R4s rule require consecutive control measurements? Is the R4s rule violated if one control is +2.4 SD and another is _1.8 SD? What's a Run? How is a "run" defined for automated random access analyzers? Does it make any difference whether a pair of control materials are analyzed immediately, one after the other, or in random order, separated by time, say one in the morning and one in the afternoon? Is it important to include patient averages to assure quality and detect preanalytical as well as analytical factors that may not be observed with control samples? How do QC procedures that make use of moving averages compare to multirule procedures? Read the answers Back to Top

FAQ's about CLIA'88, JCAHO, and CAP

How many CLIA’88 certificates should my hospital have? Who will inspect me -- HCFA (for CLIA’88), JCAHO or CAP? The hospital is accredited by JCAHO. Will JCAHO inspect all laboratory testing? The hospital is accredited by JCAHO, but the central laboratory is inspected by CAP. Will CAP also inspect POCT? Will JCAHO accept CAP’s inspection? Will CAP accept JCAHO’s inspection? Why are CLIA’88 requirements important to me when my institutions testing is inspected by JCAHO or CAP? My JCAHO laboratory is in a state that has exempt status from HCFA. Do I still need to meet specific state requirements? All testing in my institution is inspected by JCAHO and several CLIA numbers are involved. As part of quality assurance, do we just need to compare results from different methodologies under the same CLIA number? I am a doctoral scientist without board certification and I direct a laboratory that does high complexity testing. The April 24, 1995 Federal Register extended the certification requirement to September 1, 1996. Can I still be the laboratory director? Read the answers Back to Top

FAQ's about Basic QC Practices

How should I check out a new lot number of a control product? What should I do when control products with long expiration dates are not available (such as the case for many hematology control materials? What should I do when a control value is outside the calculated control limits? Do I have to record every result for a control material? Which QC data should be excluded when calculating monthly statistics (mean, standard deviation, and coefficient of variation)? Which QC results should be included in updating your mean and SD statistics? What is N? Will multirule QC assure ideal QC performance? How exactly do you apply the 41s control rule? the R4s? the 10x? What control measurements can be used when applying "bias" rules? What do I do about patient results that were reported before a problem was detected with a control rule applied across runs? Is there a multirule QC procedure for computerized immunoassay QC which fulfills all regulations? What references describe how to apply and interpret multirule QC? What training is available to help me decide what QC to use? Read the answers Back to Top

1998 Round-up of questions

What's a trend? How to apply the R4s rule? Manufacturer Ranges: Use them or lose them? Significant Figures Finding quality requirements for unregulated analytes Standard deviation ratios; verifying a new lot of reagents Where to get bias Patient-based QC and Average of Normals Read the answers Back to Top

FAQ's about Method Validation

Why is it necessary to validate method performance when the manufacturer already has? What analytical performance is needed for a laboratory test? Who should perform the validation studies in a laboratory? In setting up a new method for validation studies, how important is it to calibrate the method using primary standards instead of commerical calibrators? What performance characteristics are usually validated? What experiments are usually performed? Does linearity have to be validated? Does detection limit have to be validated for all tests? How many materials need to be analyzed in a replication experiment? What comparison method should be used in the comparison of methods experiment? Why is there so much emphasis placed on the comparison of methods experiment? Why can't the correlation coefficient be used to judge the agreement between methods in a comparison of methods study? Why are regression statistics still recommended? What's the proper way to use t-test statistics? What's the proper way to use regression statistics? What's Deming regression? What's the alternative to more complicated regression calculations? What tests are likely to have a narrow range of data and require more care? Why can't acceptability be judged by tests of significance, such as t-test and F-test? How does the "method decision chart" approach compare with the "performance criteria" approach? Where can I find more detailed protocols and statistical guidelines for method validation? Read the answers Back to Top

Method Validation course questions

This group of questions came from students in Chem 555, which is a graduate course in Clinical Chemistry at West Chester University, West Chester, PA (Fall '99). Dr. Al Caffo was the course instructor (acaffo@wcupa.edu) and an old friend from DuPont/Dade/Behring days (the "good old days"). A great opportunity to discuss method validation practices. Read this essay Back to Top

1999 Round-Up of Questions

What is N? What is a run? How can I find quality requirements for hematology? Can I make up my own control limits? The z-value and defect rates? How do you do external QC for a test where there is only a small or no peer group? Read this essay Back to Top

Your questions are encouraged!! Please send them in to westgard@westgard.com or mail them to the address below. While we can't guarantee that all questions can be answered, we regularly post a series of questions and answers here on the website so that visitors can take advantage and benefit from previous questions.

James O. Westgard, PhD, is a professor of pathology and laboratory medicine at the University of Wisconsin Medical School, Madison. He also is president of Westgard QC, Inc., (Madison, Wis.) which provides tools, technology, and training for laboratory quality management.