Cytogenetics Certification Prep: A Study Guide for the CG(ASCP) Exam
Last updated: October 22, 2026
Certification as a cytogenetic technologist tests what you know about cell culture, chromosome analysis, ISCN, molecular cytogenetics and laboratory practice. This guide sets out what to study, offers an eight-week plan, and explains how to build the karyotyping speed and accuracy the exam and the job demand.
Which certification?
In the United States the most widely held credential for cytogenetic technologists is the Technologist in Cytogenetics, CG(ASCP), awarded by the American Society for Clinical Pathology (ASCP) Board of Certification. An international version, CG(ASCPi), is available to candidates trained outside the United States.
Other routes exist for other roles and countries. Laboratory directors in the United States certify through the American Board of Medical Genetics and Genomics. Some states, including California and New York, license clinical laboratory personnel separately. Outside the United States the requirements differ again, for example the NHS Scientist Training Programme in the United Kingdom.
Check the official requirements. Eligibility routes, exam format and content outlines change. Before you plan your study, read the current CG(ASCP) content guideline and eligibility requirements on the ASCP Board of Certification website, or the equivalent for your credential.
What the exam covers
The CG(ASCP) exam is computer-adaptive. The official content guideline sets out the topics and how much weight each carries. In broad terms, expect questions in these areas:
- Specimen handling and processing: specimen types (blood, bone marrow, amniotic fluid, chorionic villi, tissue, products of conception), culture methods, harvesting, slide making and banding techniques.
- Chromosome analysis: chromosome identification, band-level assessment, recognizing numerical and structural abnormalities, normal variants, and ISCN.
- Constitutional and cancer cytogenetics: the clinical significance of common syndromes and of the recurrent abnormalities in hematologic cancers and solid tumors.
- Molecular cytogenetics: FISH probe types and interpretation, chromosomal microarray, and how they complement the karyotype.
- Laboratory operations: quality control and assurance, safety, regulations, and troubleshooting culture or banding problems.
An eight-week study plan
Adjust the pace to your experience. Someone already working at the bench may need less time on processing and more on cancer cytogenetics. Whatever your pace, practice karyotyping in every week of the plan, not only at the end.
| Week | Focus | Daily practice |
|---|---|---|
| 1 | Foundations: the cell cycle, mitosis and meiosis, nondisjunction, chromosome structure, centromere types | Identify the chromosome groups in 2 to 3 metaphases |
| 2 | Specimen processing: culture, harvest, slide making, banding methods and their troubleshooting | Full karyotypes of normal cells, 2 to 3 a day |
| 3 | Chromosome identification: landmark bands and look-alike pairs | Timed karyotypes of normal cells, tracking errors by chromosome |
| 4 | ISCN: numerical, structural and mosaic notation | Write the ISCN for every case before checking the answer |
| 5 | Constitutional abnormalities: aneuploidies, Robertsonian and reciprocal translocations, microdeletion syndromes, prenatal findings | Abnormal constitutional cases |
| 6 | Cancer cytogenetics: recurrent translocations, gains and losses, clonal evolution | Bone marrow and cancer cases |
| 7 | Molecular cytogenetics and laboratory operations: FISH, microarray, QC, safety, regulations | Mixed cases, with FISH results to interpret |
| 8 | Review your weakest areas and take practice exams under timed conditions | Timed mixed cases at exam pace |
Constitutional abnormalities to know
- Autosomal trisomies: trisomy 21, trisomy 18 and trisomy 13, including their translocation and mosaic forms.
- Sex chromosome aneuploidies: 45,X and its structural variants, 47,XXY, 47,XXX and 47,XYY.
- Translocations: Robertsonian translocations such as rob(13;14) and rob(14;21), the recurrent t(11;22)(q23;q11.2), and the segregation of balanced translocations at meiosis.
- Microdeletion and deletion syndromes: 22q11.2 deletion (DiGeorge), Williams (7q11.23), Prader-Willi and Angelman (15q11.2q13), Smith-Magenis (17p11.2), Wolf-Hirschhorn (4p16.3) and cri du chat (5p15).
- Normal variants: heterochromatin variation, inv(9)(p12q13), and acrocentric short-arm variation.
Recurrent cancer abnormalities to know
| Abnormality | Fusion or gene | Associated with |
|---|---|---|
| t(9;22)(q34;q11.2) | BCR::ABL1 | Chronic myeloid leukemia, and a subset of acute lymphoblastic leukemia. Worked case |
| t(15;17)(q24;q21) | PML::RARA | Acute promyelocytic leukemia |
| t(8;21)(q22;q22) | RUNX1::RUNX1T1 | Acute myeloid leukemia |
| inv(16)(p13.1q22) | CBFB::MYH11 | Acute myeloid leukemia |
| t(12;21)(p13;q22) | ETV6::RUNX1 | Childhood B-cell acute lymphoblastic leukemia. Usually invisible by banding and found by FISH. |
| t(8;14)(q24;q32) | MYC and IGH | Burkitt lymphoma |
| t(14;18)(q32;q21) | IGH and BCL2 | Follicular lymphoma |
| t(11;14)(q13;q32) | CCND1 and IGH | Mantle cell lymphoma, and a subset of plasma cell myeloma |
| del(5q), −7 or del(7q), +8 | Myelodysplastic syndromes and acute myeloid leukemia |
Building karyotyping speed and accuracy
Knowing the material is half the job. The other half is analyzing cells accurately at a working pace, and that only comes from volume.
- Practice every day, even if only two or three cells. Short daily sessions beat occasional long ones.
- Track your errors by chromosome. Most people have a few pairs they repeatedly confuse. Find yours and drill them.
- Commit to an answer before checking. Write the ISCN first, then compare. Checking as you go hides what you do not know.
- Time yourself once your accuracy is consistent, and aim to keep accuracy steady as your speed rises.
- Mix case types. Exams and real caseloads do not announce what is coming, so practice normal, constitutional and cancer cases together.
Keep learning
This page is for education and training. It is not medical advice and must not be used to diagnose or treat anyone. Laboratory results should be interpreted by qualified professionals following current standards.