MT 520: STILL MORE SAMPLE EXAM QUESTIONS!

Test 3: QC Planning

Sample Exam Questions for UW-Madison Med Tech Students

Posted 3/18/97

1. For a hemoglobin method, performance is to be assessed at a decision level of 9.0 g/dL. Using the CLIA PT criteria, what would be the allowable total error at this decision level?

• TE_a at 9 g/dL

2. For a calcium method, performance is to be assessed at decision levels of 7.0 mg/dL and 10.0 mg/dL. Using CLIA PT criteria, what would be the allowable total errors at these two decision levels? Express in both concentration units and percentages.

• TE_a at 7.0 mg/dL
  
  
• TE_a at 10.0 mg/dL

3. For a glucose method, performance is to be assessed at decision levels of 50 mg/dL, 110 mg/dL, and 250 mg/dL. Using CLIA PT criteria, what would be the allowable total errors at these two decision levels? Express in both concentration units and percentages.

• TE_a at 50 mg/dL
  
• TE_a at 110 mg/dL
  
• TE_a at 250 mg/dL
  

4. For activated partial thromboplastin time (APTT), it is of interest to optimize QC performance at a decision level of 35 seconds. Using CLIA PT criteria, what would be the allowable total errors at this decision level?

• TE_a at 35 seconds

5. For cyclosporin, which is a non-regulated analyte, what allowable total error would you recommend using?

6. Given a cholesterol method where the CV is 2.0% and bias is 0.0% and the laboratory is using a Levey-Jennings chart with 3SD limits and N of 2, assess the expected performance of the QC procedure.

• a. What is the quality requirement that needs to be satisfied?
  
• b. What is the critical systematic error that needs to be detected?
  
• c. What is the critical random error that needs to be detected?
  
• d. What is the expected probability of false rejection?
  
• e. What is the expected probability of detecting the critical systematic errror?
  
• f. What is the expected probability of detecting the critical random error?
  
• g. What is your assessment of the adequacy of this QC procedure?
  

7. Given the cholesterol data from a method evaluation study, a standard deviation of 5.0 mg/dL was calculated for a control having a mean of 200 mg/dL. The regression equation was Y = 4.0mg/dL + 0.98X for the data in the comparison of methods experiment.

• a. What is the quality required at a decision level of 200 mg/dL?
  
• b. What is the CV of the method?
  
• c. What is the method bias at a decision level of 200 mg/dL?
  
• d. What control rules and N do you recommend?
  
• e. Explain how you arrived at this recommendation?
  
• f. What error detection and false rejection do you expect to achieve?
  
• g. What TQC strategy do you recommend?
  

8. Given a new potassium method that shows a CV of 2.5% at a level of 3.5 mmol/L and a bias of 1.0%:

• What is the quality requirement for potassium?
  
• What QC procedure would you recommend?
  
• What Total QC strategy would you recommend?
  

9. For a new sodium method that has a CV of 0.6% and a bias of 0.5% at 140 mmol/L:

• What is the quality requirement for sodium?
  
• What QC procedure would you recommend?
  
• What Total QC strategy would you recommend?
  

10. For a new glucose method that has a CV of 3.0% and a bias of 0.0% at 100 mg/dL.

• What is the quality requirement for glucose?
  
• What QC procedure would you recommend?
  
• What Total QC strategy would you recommend?
  

11. The QC procedure for calcium on our Hitachi analyzer was originally selected based on a quality requirement of 0.5 mg/dL at a decision level of 10.0 mg/dL. Given the CLIA PT criterion that has now been defined through regulations and given our observed CV of 1.5% and bias of 2.0%, what QC procedure could be used to assure we will pass proficency testing?

12. For a potassium method, it has been recommended that you consider using 2s clinical control limits based on a medically allowable CV of 5%. Your method actually shows a CV of 3.0% based on control observations collected in your laboratory.

• a. Given a control material with a mean of 5 mmol/L, what control limits would you actually be using if you implement the recommended 2s clinical limits?
  
• b. What is the actual statistical control rule that would result if you used clinical limits with your method?
  
• c. Given the CLIA PT criterion for potassium, what would you expect for the probability of detecting critical systematic errors when N=2?
  

13. You are looking for a new potassium method. To assure that your laboratory will have no problems satisfying the CLIA PT requirement for analytical quality, what precision specification should you set for purchasing a new analyzer?

14. NCEP recommends that a triglyceride method should have a total allowable error of 14.8% and a CV of 5% or better. How much better should the CV be?

This website is best viewed by Internet Explorer or Netscape2.0 or better.