USCIS Quality Control & Assurance 3

Question 1

A batch of QuantiFERON-TB Gold Plus (QFT-Plus) tests shows that the nil tube OD value is 0.8 IU/mL, exceeding the manufacturer's cutoff of 0.70. What is the appropriate response?

Accepted Answer

Declare the results invalid for those specimens and retest if possible

Answer

An elevated nil tube suggests nonspecific stimulation or contamination, invalidating those specimens per manufacturer criteria.

Question 2

How often must a CLIA-certified laboratory performing I-693 testing document refrigerator temperature logs?

Accepted Answer

At least once per day when reagents or specimens are stored

Answer

CLIA regulations require temperature monitoring at least once daily to ensure storage conditions remain within acceptable ranges.

Question 3

A civil surgeon clinic receives a proficiency testing (PT) sample for syphilis serology and tests it as a routine patient specimen. The result is graded as unacceptable. What corrective action is required?

Accepted Answer

Perform root cause analysis and document corrective action taken

Answer

PT failures require documented root cause analysis and corrective action to maintain CLIA certification.

Question 4

In the context of USCIS medical examinations, what is the significance of lot-to-lot verification when switching to a new reagent lot?

Accepted Answer

It ensures the new lot performs equivalently to the previous lot before patient samples are tested

Answer

Lot-to-lot verification confirms that a new reagent lot produces results consistent with the established method before use on patients.

Question 5

Which of the following is an example of a pre-analytical quality control step in the I-693 laboratory process?

Accepted Answer

Verifying patient identity and checking specimen labeling before testing

Answer

Pre-analytical quality control includes all steps before testing begins, such as verifying specimen identity and integrity.

USCIS - Medical Exam Practice Test

USCIS - Medical Exam Practice Test

USCIS Quality Control & Assurance 3