SCYM Cheat Sheet 2026

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

1. Which parameter is used to distinguish doublets from single cells during flow cytometric analysis? → FSC height vs FSC area (or width)
2. Aneuploid tumor cells are identified in DNA content analysis primarily by which characteristic? → DNA index significantly different from 1.0
3. Which UMAP parameter most controls the balance between preserving local versus global data structure? → n_neighbors
4. What is the function of optical filters? → Isolate light wavelengths
5. What type of scale is often used for displaying flow data? → Logarithmic
6. A researcher sorts cells into a 96-well plate. Which sort mode is most appropriate for depositing exactly one cell per well? → Single-cell mode
7. When analyzing rare events (e.g., circulating tumor cells at 1 per million), what is the most critical acquisition parameter to adjust? → Total events collected—acquire far more events to detect rare populations
8. Which of the following defines 'precision' as validated in a clinical flow cytometry assay? → The closeness of repeated measurements of the same sample under defined conditions
9. What is the most important professional competency for SCYM certification in flow cytometry principles? → Deep knowledge combined with practical application skills
10. When selecting fluorochromes for a clinical diagnostic panel, which regulatory consideration is most critical? → Selecting FDA-cleared reagents validated for the intended clinical application
11. What role does collaboration play in immunophenotyping for SCYM professionals? → It enhances outcomes through diverse perspectives and shared expertise
12. Why must cells be filtered before analysis? → Remove clumps and debris
13. If a compensation control shows a negative population with MFI below zero after compensation software processing, what is the MOST likely cause? → Over-compensation due to an incorrectly high spillover coefficient
14. What is 'doublet discrimination' in flow cytometry? → A gating strategy to exclude cell aggregates from analysis
15. When setting up a compensation matrix, which control best represents the maximum possible spillover from a fluorochrome? → Single-color positive control using the same fluorochrome on beads or cells
16. What does a bimodal distribution on a histogram suggest about an antigen's expression in a cell population? → Two distinct subpopulations exist: one positive and one negative for the antigen
17. What happens to forward scatter (FSC) signal as cell size increases? → FSC signal increases proportionally
18. Why is it important to keep the sample concentration low when setting up a high-purity sort? → Lower concentrations reduce coincident events, improving sort purity
19. Which parameter is most commonly used as the trigger (threshold) channel in standard flow cytometry of whole blood samples? → FSC (forward scatter)
20. What is the purpose of using a 'fluorescence minus one' (FMO) control? → To determine the boundary of positivity in the presence of spectral spillover
21. Which software is commonly used for cytometry analysis? → FlowJo
22. What does mean fluorescence intensity (MFI) indicate? → Expression level
23. In flow cytometry, what does the term 'compensation' correct for? → Spectral spillover of fluorochromes into adjacent channels
24. A researcher notices that cells stained with a PE-conjugated antibody show high background fluorescence in the PE channel. What is the most likely cause? → Non-specific PE binding due to inadequate blocking or aggregated antibody
25. Which scenario represents a violation of the Specialist in Cytometry code of professional conduct? → Misrepresenting qualifications or certification status
26. A researcher notices that the PE channel signal increases over a 30-minute acquisition run even though no new cells are added. The most likely cause is: → Laser warm-up causing increasing power output
27. Which ethical principle requires SCYM professionals to act in the patient's best interest? → Beneficence
28. When quantifying CD34+ stem cells for transplantation, the ISHAGE gating strategy begins with which initial gate? → CD45 vs. side scatter to identify the leucocyte blast region
29. When conducting a risk assessment for SCYM operations, which factor should receive the HIGHEST priority? → Probability and severity of potential harm
30. In a high-speed cell sorter operating with a vibrating nozzle, the droplet break-off frequency is determined by: → The piezoelectric crystal oscillation frequency applied to the nozzle