TB Test Quality Assurance and Improvement 3 — Questions and Answers
Question 1: A health department reviews TB testing records and finds that 30% of two-step TST results lack documentation of the second step. This finding is BEST addressed by:
- Implementing a standardized tracking log that flags incomplete two-step sequences (Correct answer)
- Eliminating the two-step protocol for low-risk populations
- Requiring physicians to approve each two-step initiation
- Retraining only the staff member with the most incomplete records
Correct answer: Implementing a standardized tracking log that flags incomplete two-step sequences
A systematic tracking tool prevents incomplete two-step testing by ensuring every initiated sequence is flagged until both steps are documented.
Question 2: Which of the following BEST describes the purpose of proficiency testing in a TB IGRA laboratory?
- To verify that the laboratory consistently produces accurate results using standardized samples (Correct answer)
- To train new laboratory technicians on IGRA procedures
- To compare the lab's positivity rate with national averages
- To satisfy billing and reimbursement requirements
Correct answer: To verify that the laboratory consistently produces accurate results using standardized samples
Proficiency testing uses standardized samples with known results to confirm that a laboratory's testing process reliably produces accurate outcomes.
Question 3: A clinic implements a new electronic reminder system to ensure TST results are read within 48–72 hours. After one month, unread results decrease by 40%. In the PDSA framework, this evaluation occurs in which phase?
- Study (Correct answer)
- Plan
- Do
- Act
Correct answer: Study
The Study phase involves analyzing data collected during the Do phase to determine whether the change produced the desired improvement.
Question 4: Which of the following is a leading indicator of TB testing quality, rather than a lagging indicator?
- Staff competency assessment scores before testing season begins (Correct answer)
- Number of false-negative results reported last quarter
- Patient complaint rate related to TB testing errors
- Percentage of indeterminate IGRA results in the prior year
Correct answer: Staff competency assessment scores before testing season begins
Staff competency scores are leading indicators because they predict future performance before errors occur, unlike lagging indicators that measure past outcomes.
Question 5: A root cause analysis (RCA) of repeated TST reading errors reveals that the measuring ruler provided is not calibrated in millimeters. This is categorized as a:
- Equipment/materials failure (Correct answer)
- Human error
- Communication failure
- Policy/procedure gap
Correct answer: Equipment/materials failure
An improperly calibrated or inappropriately scaled tool is an equipment and materials failure, not a human error, and requires replacement of the instrument.
Question 6: According to quality improvement principles, which practice MOST effectively sustains long-term improvements in TB testing accuracy?
- Embedding the change into standard operating procedures and ongoing staff training (Correct answer)
- Conducting a one-time retraining session after each identified problem
- Increasing supervisory oversight during peak testing periods only
- Reporting all errors to external accreditation bodies
Correct answer: Embedding the change into standard operating procedures and ongoing staff training
Sustainability requires that improvements become part of standard procedures and reinforced through ongoing training rather than one-time responses.
Question 7: A TB clinic uses a control chart to monitor daily IGRA positivity rates. A point falls outside the upper control limit. This MOST likely indicates:
- A special cause variation requiring investigation (Correct answer)
- Normal random variation in the testing population
- That the control limits need to be recalculated
- That the IGRA kit lot should be changed immediately
Correct answer: A special cause variation requiring investigation
A point outside control limits signals special cause variation—a non-random event that warrants investigation to identify an assignable cause.
TB Test Quality Assurance and Improvement 3
A health department reviews TB testing records and finds that 30% of two-step TST results lack documentation of the second step.
This finding is BEST addressed by: