For Patients
Understanding Genetic Tests
A Simple Guide for Everyone
Genes are like instruction manuals in every cell of our body.
Genetic tests help doctors read these instructions to understand, diagnose, treat, and prevent many health conditions.
Accurate
Scientifically validated testing
Advanced
State-of-the-art technology
Expert Guidance
Genetic counselling at every step
Better Outcomes
Informed decisions for healthier lives
10 Types of Genetic Tests Explained in Detail
Karyotyping
What Is It?
A test that examines the number, size and structure of all chromosomes under a microscope.
What It Can Detect
- Extra chromosomes
- Missing chromosomes
- Large chromosome changes (rearrangements)
When It's Recommended
- Developmental delay, intellectual disability
- Recurrent pregnancy loss
- Infertility evaluation
- Multiple congenital anomalies
Example
Detects conditions like Down syndrome (extra chromosome 21) or Turner syndrome (missing X chromosome).
Fluorescence In-Situ Hybridization (FISH)
What Is It? A targeted test that uses fluorescent probes to find specific DNA sequences on chromosomes.
What It Can Detect
- Small missing or extra pieces of chromosomes
- Specific microdeletions/microduplications
- Specific chromosome rearrangements
When It's Recommended
- When a particular genetic change is suspected
- To confirm an abnormality seen on karyotype
- To detect subtype of Cancer
Example: Detects 22q11.2 deletion syndrome (DiGeorge syndrome).
Chromosomal Microarray (CMA)
What Is It? A high-resolution test that scans all chromosomes for tiny gains or losses of DNA.
What It Can Detect
- Small deletions (microdeletions)
- Small duplications (microduplications)
- Copy number variations (CNVs) across the genome
When It's Recommended
- Developmental delay, autism
- Multiple congenital anomalies
- Unexplained intellectual disability
- Recurrent pregnancy loss
Example: Detects very small deletions or duplications that karyotyping cannot see.
Multiplex Ligation-dependent Probe Amplification (MLPA)
What Is It? A test that checks specific genes for missing (deleted) or extra (duplicated) pieces.
What It Can Detect
- Missing exons/genes
- Extra copies of exons/genes
- Gene-level deletions or duplications
When It's Recommended
- When a single-gene disorder is suspected
- To confirm deletions/duplications detected by other tests
Example: Detects deletions in genes causing Duchenne muscular dystrophy.
Sanger Sequencing
What Is It? A method that reads the DNA letter by letter (A, T, G, C) in a specific region.
What It Can Detect
- Small changes in DNA letters (point mutations)
- Small insertions or deletions
When It's Recommended
- To confirm a known genetic variant
- When a targeted region needs very accurate results
Example: Detects a single letter change in a gene that causes a disease.
Next Generation Sequencing (NGS)
What Is It? A powerful technology that reads millions of DNA pieces at the same time to analyze many genes or even the whole genome.
What It Can Detect
- Variants across many genes
- Small and large changes
- Complex variants
When It's Recommended
- Rare diseases with unclear cause
- Cancer genetics
- Pharmacogenomics
- Carrier screening panels
Example: Helps identify the genetic cause of a rare inherited disorder.
Human Leukocyte Antigen (HLA) Typing
What Is It? A test that identifies HLA markers—important proteins found on immune cells.
What It Can Detect
- HLA types (Class I and Class II) that determine immune system compatibility
When It's Recommended
- Organ or stem cell transplant matching
- Bone marrow donor selection
Example: Helps find the best donor match for a bone marrow transplant.
Quantitative Fluorescent PCR (QF-PCR)
What Is It? A rapid PCR-based test that measures specific chromosome markers to determine their number.
What It Can Detect
- Extra or missing copies of specific chromosomes (13, 18, 21, X, Y)
When It's Recommended
- Prenatal testing for quick results
- When rapid information is important
Example: Used to quickly detect Down syndrome (extra chromosome 21).
Carrier Screening
What Is It? A test that checks whether a person carries genetic changes for inherited conditions without having the disease.
What It Can Detect
- Variants in genes that can be passed to children
When It's Recommended
- Preconception planning
- Family history of genetic disorders
- Certain ethnic backgrounds
Example: Detects carrier status for Thalassemia or Cystic Fibrosis.
Preimplantation Genetic Testing (PGT)
What Is It? A test performed on embryos created through IVF before they are transferred to the uterus.
What It Can Detect
- PGT-A: Extra or missing chromosomes
- PGT-M: Known single-gene disorders
- PGT-SR: Structural chromosome rearrangements
When It's Recommended
- Recurrent IVF failures
- Known genetic disorders in the family
- Advanced maternal age
Example: Helps select embryos with the correct number of chromosomes before implantation.
At a Glance: Which Test Does What?
| Test | Looks At | Detects | Resolution / Scope* | Turnaround Time* | Sample Type* |
|---|---|---|---|---|---|
| Karyotyping | All chromosomes | Large changes (extra/missing/rearrangements) | 5–10 Mb | 7–14 days | Blood / Amniotic fluid / CVS |
| FISH | Specific regions | Targeted deletions/duplications/rearrangements | 100 kb – 1 Mb | 1–3 days | Blood / Amniotic fluid / tissue |
| Chromosomal Microarray (CMA) | Whole genome | Small deletions/duplications (CNVs) | 50 kb – 100 kb | 7–10 days | Blood / Amniotic fluid |
| MLPA | Specific genes/exons | Exon or gene level deletions/duplications | 1–10 exons | 3–5 days | Blood |
| Sanger Sequencing | Specific DNA region | Small variants (point mutations, small indels) | 1-base | 3–7 days | Blood / Saliva |
| NGS (Panels / Exome / Genome) | Many genes / whole exome/genome | Wide range of variants | 1-base | 2–4 weeks | Blood / Saliva |
| HLA Typing | HLA genes | HLA types (Class I & II) | Gene level | 3–7 days | Blood / Buccal swab |
| QF-PCR | Specific chromosomes | Extra or missing copies of chromosomes | High (targeted) | 1–2 days | Amniotic fluid / CVS |
| Carrier Screening | Many genes | Carrier status for inherited conditions | Varies by panel | 1–3 weeks | Blood / Saliva |
| PGT | Embryo DNA | Chromosome number / single gene / structural | High | 1–2 weeks | Embryo cells |
*Turnaround time may vary depending on test type and laboratory.
How Genetic Tests Help
- Find the cause of unexplained health issues
- Guide treatment and management
- Assess risk for future health conditions
- Help in family planning and pregnancy care
- Enable personalized medicine
Things to Remember
- A test result is not a diagnosis on its own.
- Results can be Normal, Variant of Uncertain Significance (VUS), or Pathogenic.
- Genetic counseling helps you understand the results in the right context.
- Always discuss with your doctor or genetic counsellor
We Are Here to Guide You
Choosing the right test can be confusing. Our genetic counsellors and experts will help you select the most appropriate test based on your medical and family history.