How Long Does Genetic Testing Take? A Complete Timeline Explained

Introduction

Getting genetic test results can make people anxious, nervous or even excited. Many times, waiting for genetic test results can feel like an eternity. However, understanding the factors that shape the genetic testing timeline is key to managing expectations. Knowing the genetic testing timeline helps manage expectations and reduce anxiety in people. In this comprehensive blog, we’ve got you a step-by-step overview of the DNA test results timeline, explaining factors that affect turnaround time, the expected duration for different test panels, and advice on managing the results waiting process.

Understanding Genetic Testing Timelines: Key Factors

To understand why genetic testing takes slightly longer than routine investigations, let’s look at the factors that affect the timeline.

What Affects How Long Testing Takes?

Several factors influence how long genetic testing takes:

• Test complexity & scope: The results of targeted single-gene tests often come back faster than those from multi-gene panels, whole exome sequencing (WES), and whole genome sequencing (WGS), as these require more complex processing.
• Testing technology used: PCR (polymerase chain reaction) is the fastest (within days), while next-generation sequencing (NGS) and Sanger sequencing typically take longer.
• Laboratory capacity: Laboratories with high sample volumes, staff shortages, or equipment limitations may increase genetic testing turnaround time, resulting in delayed results.
• Sample quality: Poor-quality or mislabeled samples may require recollection, adding 1–2 weeks to processing time and delaying genetic testing results.
• Result interpretation: Complex or ambiguous findings in genetic tests may take longer to interpret, especially when variants of uncertain significance are discovered. This can delay genetic testing turnaround times.
• Urgency level: In some cases, healthcare professionals or genetic counsellors label a sample ‘urgent’ or ‘stat, indicating they need to be prioritised and processed faster than routine panels. The turnaround time for these genetic tests is usually shorter.

General Timeline Ranges

Here’s the tentative timeline for routine genetic tests:

Certifications like GMP and ISO in laboratories also ensure high accuracy with multiple checks, which may lengthen the process, but guarantee reliable results.

Different tests have different genetic testing timelines.

Prenatal and Reproductive Genetic Testing Timelines

• Non-Invasive Prenatal Testing (NIPT)
  • This genetic test is usually done before the 12-week ultrasound.
  • To perform this test, a blood sample is collected at a prenatal visit.
  • The results of this genetic test typically arrive in 7–14 days, while rapid (stat) results can be made available in 3–5 days.

• Preimplantation Genetic Testing (PGT)
  • This test is a part of fertility treatments like IVF and is conducted on embryos 5 to 6 days after fertilisation.
  • The test is usually performed before the embryo is transferred to the mother’s uterus.
  • The results of a PGT can take 7 to 14 days.

• Carrier Screening
  • This genetic test is performed on individuals to determine if they are carriers of inheritable conditions.
  • It helps prevent the trait from being passed on to their children.
  • If an individual is positive for a specific trait (a carrier), partner testing may be recommended.
  • The typical carrier screening results time is 4–5 weeks (standard panels).

• Prenatal Diagnostic Testing

Other prenatal diagnostic testing includes:

• Amniocentesis/CVS: Test results take around 7–14 days.
• Karyotype: The test results usually take 10-14 days, while microarray analysis takes 7–10 days.

Newborn Screening Timeline

Newborn screening includes routine genetic tests performed after a child is born. The timeline for the same includes the following stages:

• Blood collection: Heel prick performed 24–48 hours post-birth.
• Lab processing: It takes 3–7 days for the lab to process the results, and the results are shared with the paediatrician at the earliest.
• Abnormal results: If abnormal results are detected, the paediatrician is notified immediately (within 24–48 hours).
• Follow-up confirmatory testing: Confirmatory diagnostic results may take an additional 1–2 weeks.

Cancer Genetic Testing Timelines

Genetic testing for cancer is increasingly becoming common as more people with a family or personal history of cancer wish to know their risks and mitigate them at the earliest. This makes cancer genetic testing timelines essential to understand.

BRCA1/BRCA2 Testing:(Hereditary Cancer Risk):

• The blood sample is collected, and standard results take around 4–5 weeks to arrive.
• For a single-site test (for a known family mutation), results may take 1 to 2 weeks.

Comprehensive Hereditary Cancer Panels

In addition to BRCA1/BRCA2 testing, other cancer panels may be needed based on symptoms and the suspected diagnosis. The timelines for these genetic tests may vary:

• Multi-gene panels covering 20–80+ genes take 3–4 weeks. Larger panels may require 4–6 weeks.
• This is because NGS platforms process multiple genes but need extra time for complex variant analysis.

Diagnostic and Rare Disease Testing Timelines

Genetic testing is instrumental in diagnosing rare diseases using advanced techniques. The timelines for these genetic tests are:

• Single Gene Testing: For a targeted mutation test, you can expect results in 1–2 weeks, whereas complete sequencing may take 2–4 weeks.
• Gene Panel Testing: Genetic test results for small gene panels (that analyse 5 to 20 genes) take 2 to 4 weeks, while larger panels (analysing 50-100+ genes) can take between 4 to 6 weeks.
• Whole Exome Sequencing (WES): Test results are available in 4 to 6 weeks, whereas rapid protocols may be available in 14 to 18 days in urgent cases.
• Whole Genome Sequencing (WGS): These test results typically take 4 to 6 weeks, but in research settings, they may sometimes take several months to arrive.
• Chromosomal Microarray: This genetic test detects deletions or duplications in the gene code, and results usually arrive in 10-14 days.

Other Specialised Testing Timelines

Genetic testing is versatile and highly robust in detecting blood disorders, infectious diseases, and pharmacogenomics. The test turnaround times vary across these specialised testing scenarios.

• Blood disorders: Thalassemia and sickle cell test results typically arrive in 1–2 weeks, whereas larger blood disorder panels may take around 3–4 weeks.
• Pharmacogenomics: Medication metabolism panels results generally arrive in 4–6 weeks, but rapid PCR-based results are possible in days.
• HLA typing for transplant: Low-resolution typing takes 3–5 days, whereas high-resolution typing can take around 1–2 weeks.
• Infectious disease genetics: HPV/STD PCR panel test results are available in 3–7 days, but genetic tests for pathogen identification can take 1–2 weeks.
• Flow cytometry (Immune/Blood Disorders): Some results are available as early as 1–3 days, but extended workups may take longer, and results are available in 1–2 weeks.

The Testing Process: What Happens During Each Stage

With a broad picture of the tentative timelines for different types of genetic tests, let’s understand what happens at every stage of these tests.

Stage 1: Sample Collection (Day 0)

• An appropriate sample is collected (blood, saliva or a tissue biopsy), appropriately labelled and documented
• The sample is transported to the laboratory (same day or next day)
• Controlled temperature conditions (2-8°C) are maintained

Stage 2: Laboratory Receipt and Accessioning (Days 1-2)

• The sample is registered in the laboratory system
• Quality of the sample is checked: Volume, integrity, labelling verification
• Sample is added to the testing queue
• Priority is determined (routine vs. urgent)

Stage 3: DNA/RNA Extraction (Days 2-4)

• Isolating genetic material from a sample
• Quality assessment of extracted DNA/RNA is performed
• Concentration and purity verification
• The sample is prepared for analysis

Stage 4: Testing and Analysis (Days 5-30+)

• Specific tests are performed on the sample (e.g., PCR, NGS, microarray).
• Multiple quality control checkpoints
• Data generation and initial analysis
• The technology platform determines the duration
• NGS requires sequencing, alignment, and variant calling

Stage 5: Bioinformatics Analysis (Days 15-40 for complex tests)

• The variant is identified and filtered
• Comparison to the reference genome
• Classification of variants (pathogenic, benign, VUS)
• Database consultation for known mutations
• Most time-intensive for WES/WGS

Stage 6: Clinical Interpretation and Review (Days 20-50+)

• Medical geneticist or genetic counsellor review
• Variant significance determination
• Literature review for novel findings
• Correlation with clinical information
• Report preparation

Stage 7: Result Reporting (Final 1-3 days)

• Report generation and verification
• Quality assurance review
• Release to the ordering physician
• Notification to the patient through the provider

What Can Delay Genetic Testing Results?

Despite the meticulous process followed by certified labs, there are several reasons why genetic testing results can be delayed:

• Sample quality issues, such as inadequate or contaminated samples, require recollection, increasing turnaround time.
• Technical or equipment failures can add up to 1–2 weeks.
• Inconclusive results or the presence of complex variants may require supplementary analyses or expanded testing, requiring more processing time.
• Provider or insurance delays, such as waiting for pre-authorisation or additional clinical info, cause variable delays.
• Lab volume & logistical issues, such as holidays, staffing shortages, or shipping/courier problems, can delay receipt and processing.

When are Expedited or Stat Testing Required?

In critical clinical scenarios, such as pregnancy management, cancer treatment, transplant planning or suspected newborn disorders, expedited genetic testing is possible.

Stat Testing Timelines

• NIPT can be rushed to 3–5 days
• Urgent cancer panels in 1–2 weeks
• Emergency confirmatory testing for newborns can be made available within 24–48 hours.

However, not all tests (especially WES/WGS) can be expedited due to analysis complexity. It is also essential to understand that rushed testing does not compromise quality.

What to Do While Waiting for Results?

While you wait for your genetic testing results, here are a few things you can do:

• Confirm the expected results timeline and how you will be notified.
• Keep up all medical follow-ups.
• Prepare questions for your healthcare provider or genetic counsellor to discuss once results arrive.
• Follow up with the lab or healthcare facility if you do not receive results within the promised window, especially if needed urgently.
• Arrange counselling for helping patients navigate complex or unexpected findings.
• Notify providers promptly if your health status changes or urgent results are required.

Conclusion: Understanding Timelines Reduces Anxiety

The turnaround time for genetic tests varies from a few days to several months, based on the complexity, technology, laboratory processes, and clinical urgency. While waiting for your genetic testing results can be stressful, maintaining clear communication with your healthcare team and staying informed about the process are crucial. Ask your provider about the turnaround time for the specific genetic test you have undergone.

Frequently Asked Questions

1. How long does genetic testing take?

Genetic test results can take anywhere from 3 days to 4-6 weeks to arrive, depending on the complexity of the test and what is being studied.

2. What is the fastest type of genetic testing?

Results for real-time PCR and some targeted panels are available within 1–7 days.

3. Why does whole-exome sequencing (WGS) take so long?

Due to the massive data analysis, multiple validation steps, and in-depth interpretation required for accuracy, WGS takes a long time.

4. Can genetic testing be expedited?

In some cases where urgent results are needed, genetic testing can be expedited to deliver results quickly.

5. What causes delays in genetic testing?

Sample quality issues, laboratory or equipment issues, complex results, missing information, insurance, and logistical roadblocks are common reasons for delays in genetic testing.

6. How are the results of genetic testing communicated?

Typically, via the healthcare provider, who will arrange an appointment or phone call to discuss the report.