Analyzers and Blood Films questions for the DHA hematology scientist exam.
This topic covers the measurement principles of automated hematology analyzers, the interpretation of flags and scatterplots, sources of spurious results and the preparation and review of peripheral blood films. Candidates for the DHA clinical scientist exam should know when automated results need a film review before release and how to resolve common analytical interferences.
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220
analyzers and blood films practice questions
- 20%
- of the exam
- 5
- subtopics
- Oct 2026
- updated
Inside this topic.
The subtopics our analyzers and blood films questions cover.
- Morphology
- Troubleshooting
- Principles
- Flow Cytometry
- Interpretation
Key facts to remember.
High-yield analyzers and blood films points to revise before the exam.
- 1
Impedance (Coulter principle) counting detects cells by the change in electrical resistance as they pass through an aperture, with pulse height proportional to cell volume.
- 2
EDTA-dependent platelet clumping causes pseudothrombocytopenia, which is confirmed on the blood film and often resolved by recollecting into citrate.
- 3
Cold agglutinins cause a falsely low RBC count and hematocrit, a falsely high MCV and a markedly raised MCHC; warming the sample to 37°C corrects the indices.
- 4
Analyzers usually measure hemoglobin with a cyanide-free sodium lauryl sulfate method; lipemia and very high white cell counts can falsely raise the result.
- 5
A well-made wedge film has a feathered edge and a monolayer area where red cells just touch, which is where morphology and the differential are assessed.
Sample questions with answers.
10 practice questions for the Hematology - Clinical Scientist - DHA Healthcare Professional Licensing (Analyzers and Blood Films). Pick an answer to see if you're right, with a full explanation.
Question 1
A CBC analyzer flags "RBC Dimorphic Population." The histogram shows two peaks. The patient was recently treated for Iron Deficiency. What is the likely cause?
Question 2
A 4-year-old child presents with a "High WBC" (80 x 10^9/L). The smear shows small blasts with "clumped" chromatin and scant cytoplasm. TdT is positive. Which lineage is most likely?
Question 3
A 5-year-old child presents with "Bite Cells" and "Blister Cells" on the smear following treatment for an infection. This is typical of:
Question 4
What is the clinical significance of a "Dohle Body"?
Question 5
What is the corrective action if a CBC sample shows platelet satellitism?
Question 6
A "Thrombin Time" (TT) is performed. The result is 120 seconds. The "Reptilase Time" is 18 seconds (Normal). What is the most likely interference in the sample?
Question 7
In "Flow Cytometry," "Gating" refers to:
Question 8
Which "Hemoglobin" variant is the most common worldwide and is characterized by a substitution of Lysine for Glutamic acid at the 6th position of the Beta chain?
Question 9
Which "Coagulation Test" is used specifically to monitor "Low Molecular Weight Heparin" (LMWH) therapy?
Question 10
"Hydrodynamic Focusing" in automated analyzers is used to:
Other topics in this exam.
Questions, answered
Review rules vary between laboratories but typically include analyzer flags for blasts, immature granulocytes, atypical lymphocytes or nucleated red cells, values outside set limits and first-time abnormal results. The International Consensus Group for Hematology Review published widely used criteria that many laboratories adapt locally. At this level you should be able to justify a review from the overall pattern of results, not just a single flag.
Look for internally inconsistent results, such as an MCHC above about 370 g/L or a hemoglobin that does not match the hematocrit, and compare with the film and previous results. Common causes include cold agglutinins, lipemia, hemolysis, platelet clumps, red cell fragments counted as platelets and nucleated red cells counted as white cells. Knowing the corrective action for each, such as warming, plasma replacement or a manual count, is often what the question is really testing.
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All 220 analyzers and blood films questions, with explanations and a readiness score for this topic.