Laboratory Operations questions for the DHA lab exam.
Laboratory Operation covers quality control and quality assurance, instrument calibration and maintenance, specimen handling, laboratory statistics and calculations. Candidates for the DHA exam are expected to interpret quality control charts, apply Westgard rules and understand how a laboratory keeps its results reliable and meets accreditation requirements.
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529
laboratory operations practice questions
- 8%
- of the exam
- 8
- subtopics
- Oct 2026
- updated
Inside this topic.
The subtopics our laboratory operations questions cover.
- Laboratory Operations
- Quality Management
- Quality Control
- Westgard Rules
- Statistics
- Phlebotomy
- Specimen Rejection – Sputum Quality
- Quality Assurance
Key facts to remember.
High-yield laboratory operations points to revise before the exam.
- 1
On a Levey-Jennings chart, a 1-3s violation (one control beyond the mean plus or minus 3 SD) is a rejection rule that most often indicates random error.
- 2
A shift is an abrupt change in the control mean, while a trend is a gradual drift in one direction; both suggest systematic error.
- 3
Accuracy is closeness to the true value, whereas precision is the reproducibility of repeated measurements, expressed as SD or coefficient of variation.
- 4
Coefficient of variation (CV) = (standard deviation / mean) x 100, which allows precision to be compared between methods or concentration levels.
- 5
Diagnostic sensitivity is the proportion of people with a disease who test positive; specificity is the proportion without the disease who test negative.
Sample questions with answers.
10 practice questions for the DHA Medical Laboratory Technologist & Technician Licensing Examination - Dubai UAE (Laboratory Operations). Pick an answer to see if you're right, with a full explanation.
Question 1
Which disinfectant kills spores?
Question 2
A test with high specificity is best used to:
Question 3
A gradual trend on a Levey–Jennings chart suggests?
Question 4
Deionization of laboratory water primarily removes which components?
Question 5
Which lab value is most affected by prolonged tourniquet application?
Question 6
A control serum has a mean of 5.8 mg/dL and SD of 0.15 mg/dL. What are ±2 SD limits?
Question 7
Which chemical is commonly used as a fixative but is toxic and carcinogenic?
Question 8
The main function of an external quality assessment (EQA) program is to:
Question 9
Which statistic BEST reflects reproducibility of results?
Question 10
Which fire extinguisher is appropriate for electrical fires?
Other topics in this exam.
Questions, answered
Learn 1-2s (warning), 1-3s, 2-2s, R-4s, 4-1s and 10x, along with whether each mainly detects random or systematic error. R-4s and 1-3s usually point to random error, whereas 2-2s, 4-1s and 10x point to systematic error. Practice applying the rules to sets of control values rather than memorizing the names alone.
Expect dilutions and dilution factors, preparing solutions of a given molarity or percentage, C1V1 = C2V2 problems and simple statistics such as mean, SD and CV. Write the units at every step to avoid errors. These questions reward steady practice more than memorization.
Ready to practise laboratory operations?
All 529 laboratory operations questions, with explanations and a readiness score for this topic.