CSMLS Cheat Sheet 2026

The 30 highest-yield CSMLS facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which of the following pieces of equipment provides protection from aerosols while aliquoting specimens? → Biological Safety Cabinet
2. Restriction fragment length polymorphism (RFLP) analysis detects genetic variation by: → Identifying sequence changes that create or abolish restriction enzyme recognition sites
3. Fluorescence in situ hybridization (FISH) is primarily used in molecular diagnostics to: → Detect specific DNA sequences or chromosomal rearrangements in intact cells
4. The VDRL and RPR tests are used to screen for: → Syphilis
5. Which of the following scenarios would most likely result in a mixed-field reaction in the forward ABO grouping? → A Group B patient recently transfused with Group O red blood cells.
6. Which cell type is the primary producer of antibodies? → Plasma cell
7. A dark brown pigment is noted on formalin-fixed, hematoxylin, and eosin-stained sections. What action can prevent this from occurring? → Maintain formalin at a neutral pH
8. Rheumatoid factor (RF) is an autoantibody directed against: → The Fc portion of IgG
9. Which of the following is an important pre-analytical consideration when interpreting thyroid function tests during pregnancy? → Trimester-specific reference intervals should be used for TSH and free T4.
10. Which electrophoresis technique is best suited for separating very large DNA fragments greater than 50 kilobases? → Pulsed-field gel electrophoresis (PFGE)
11. A patient's blood gas results on room air are: pH 7.25, pCO2 60 mmHg, HCO3- 24 mmol/L. Which of the following conditions is most consistent with these findings? → Respiratory acidosis
12. Which of the following situations will cause mast cells to turn blue during metachromatic staining? → Decreased pH of toluidine blue
13. What is the primary purpose of the denaturation step in PCR? → To separate double-stranded DNA into single strands
14. Analytical sensitivity in a molecular diagnostic test refers to: → The lowest concentration of target nucleic acid reliably detected above background
15. What is the systematic approach to reviewing a task or job to identify hazards? → Risk assessment
16. In cerebrospinal fluid (CSF) analysis, xanthochromia (yellow discoloration) indicates: → Previous subarachnoid hemorrhage
17. What class of biological safety cabinet (BSC) is most commonly used for routine work with Risk Group 2 organisms in Canadian laboratories? → Class II Type A2
18. What is the correct order for removing personal protective equipment (PPE) after working with potentially infectious specimens? → Gloves, gown, eye protection, mask
19. Which next-generation sequencing (NGS) platform uses fluorescently labeled reversible terminator nucleotides incorporated one base at a time? → Illumina sequencing by synthesis
20. Amniotic fluid bilirubin (delta OD450) measured by spectrophotometry is used to assess: → Severity of fetal hemolytic disease
21. The normal white blood cell count in cerebrospinal fluid is: → 0–5 cells/µL
22. What is the principle of the Jaffe reaction for measuring creatinine? → Creatinine reacts with picric acid in an alkaline solution to form a red-orange complex.
23. A prozone phenomenon in agglutination testing occurs when: → Antibody is in excess causing false-negative results
24. In a direct Coombs (DAT) test, a positive result indicates: → Antibodies or complement bound to red blood cells in vivo
25. The presence of Auer rods within blasts on a peripheral blood smear is most strongly associated with which of the following conditions? → Acute Myeloid Leukemia (AML)
26. Which of the following actions should be taken when tissue sections stained with hematoxylin and eosin show pale cytoplasmic staining? → Check the pH of eosin and adjust with acetic acid if necessary
27. Which immunoglobulin class is the primary antibody in secretions such as saliva and breast milk? → IgA
28. What is the most important step in preventing infection? → Hand washing
29. What type of extinguisher is used for metal fires? → Class D dry chemical
30. According to Canadian Standards Association (CSA) Z902 standards, what is the correct storage temperature range for Platelet concentrates? → 20 to 24°C