Quality assurance: samples, reagents, procedures

6 ASCP MLS practice questions on Quality assurance: samples, reagents, procedures, part of Blood Banking. The first 6 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Medium

   A type and screen tube shows the patient's first name spelled differently from the request; the medical record number matches. What should the laboratory do?

   1. APhone the ward and accept on verbal confirmation
   2. BReject it and collect a new sample
   3. CCorrect the spelling on the tube label
   4. DAccept it, since the record number matches

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   Answer: B · Reject it and collect a new sample

   Any discrepancy between the tube and the request means the sample's identity cannot be trusted. The sample is rejected and a new one is collected with correct identification at the bedside. Relabeling a pretransfusion sample is not allowed. Strict rules prevent wrong-blood-in-tube errors, a leading cause of ABO-incompatible transfusion.

   • A: Verbal confirmation cannot fix a labeling discrepancy.
   • C: Relabeling a pretransfusion sample is not allowed.
   • D: One matching identifier does not make up for a discrepancy.

2. Question 2 · Medium

   How often must routine blood bank antisera and reagent red cells be tested with quality control?

   1. AOnce each week
   2. BOnce each month
   3. COnly when a new lot arrives
   4. DOn each day of use

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   Answer: D · On each day of use

   Antisera, reagent red cells and antiglobulin reagents are checked for expected reactivity on each day they are used. Positive and negative controls show the reagents work and are specific. New lots are also checked before use. Results and any corrective actions are recorded.

   • A: Weekly checks would leave days of untested reagent use.
   • B: Monthly checks would leave weeks of untested reagent use.
   • C: Lot checks alone do not detect deterioration or contamination during use.

3. Question 3 · Easy

   A pretransfusion blood sample label must include at least:

   1. ATwo patient identifiers and the collection date
   2. BThe requesting doctor's name and phone
   3. CThe patient's ABO group from records
   4. DThe patient's surname and ward number

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   Answer: A · Two patient identifiers and the collection date

   AABB requires two independent patient identifiers and the date of collection on the tube. There must also be a way to identify the person who collected it. The tube is labeled at the bedside in the patient's presence. The details must match the request exactly.

   • B: The doctor's details do not identify the patient.
   • C: A recorded ABO group is a test result, not an identifier.
   • D: A surname and ward are not unique and can change.

4. Question 4 · Hard

   A patient with no transplant history types group O today, but the blood bank record from last month shows group A. What is the most likely cause, and the correct action?

   1. AWeakened A antigen; report the older group A
   2. BA change after recent transfusion; report O
   3. CA reagent error; report the newer group O
   4. DWrong blood in tube; collect a new sample

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   Answer: D · Wrong blood in tube; collect a new sample

   Without a transplant, a person's ABO group does not change, so the most likely cause is a misidentified sample, now or last month. A new sample is drawn independently and tested, and the event is investigated as a safety incident. Group O red cells are given if transfusion cannot wait. Checking against history is one of the most important safeguards in the blood bank.

   • A: Reporting either result without resolving the discrepancy risks an ABO-incompatible transfusion.
   • B: Transfusion does not change a patient's own ABO group.
   • C: A reagent error is less likely than misidentification and would show in QC; neither result can be reported yet.

5. Question 5 · Hard

   The morning QC shows that anti-B fails to react with B cells. What should be done before any ABO results are reported?

   1. AHold results, replace the reagent, pass QC, then retest
   2. BReport results with a note about the QC failure
   3. CRepeat only the patient tests with the same reagent
   4. DSubstitute anti-A,B for anti-B and report as usual

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   Answer: A · Hold results, replace the reagent, pass QC, then retest

   Patient results cannot be reported unless QC is acceptable. The cause, such as a contaminated, expired or wrong vial, is investigated and the reagent replaced. QC is repeated and must pass before patient samples are retested. The failure, investigation and corrective action are documented, and earlier results are reviewed if needed.

   • B: Results from a failed QC run must not be reported.
   • C: Repeating with the same failed reagent does not fix the problem.
   • D: Anti-A,B cannot replace anti-B, because it reacts with both A and B cells.

6. Question 6 · Hard

   At 02:10, a hypotensive 45-year-old man with a gastrointestinal bleed needs red cells urgently, and the physician signs an emergency release request. The emergency department sends a pretransfusion tube with a bedside-printed label that shows his full name and medical record number but no collection date; the electronic collection record names the nurse who drew it. The requisition is complete and matches the label. The blood bank has no previous record for him. The most appropriate action is:

   1. AIssue group O red cells and request a new sample
   2. BType this tube and issue group-specific red cells
   3. CAccept the tube using the date on the requisition
   4. DHave the nurse write the date on the tube label

   Answer and explanation in LearnFree account