What affects the turnaround time of whole-exome sequencing, from sample checks and sequencing to bioinformatics and clinical sign-off.
There is no single fixed turnaround time
Turnaround time varies with the laboratory, order volume, sample quality, the number of relatives tested and the level of clinical interpretation required. Some laboratories quote several weeks, and prioritized services may be available, but no timeframe applies universally.
The meaningful estimate is the written turnaround time provided by the laboratory for your specific service. Time spent sequencing is not the same as time required to issue a reviewed, signed clinical report.
Stage 1: sample receipt and assessment
The laboratory checks the patient identifiers, request form, sample type and sample quality. Incomplete documentation or inadequate sample quality may require replacement or clarification.
This is part of quality assurance and does not imply anything about the patient’s genetics. Check collection requirements and sample shipping arrangements before your appointment.
Stage 2: DNA extraction and sequencing
DNA is extracted, a sequencing library is prepared, target regions are enriched and an NGS instrument reads the sample. Laboratories may batch samples, which can affect the scheduling of a sequencing run.
If quality-control metrics fail, part of the laboratory process may need to be repeated. A reliable result is more important than an artificially short waiting time.
Stage 3: data analysis and variant prioritization
Sequencing reads are processed and aligned to a reference genome. Potential variants are called, filtered and assessed alongside clinical findings and current scientific evidence.
Complex cases and unclear variants may require more review. Detailed clinical notes and a useful pedigree help the team prioritize the right findings, although they cannot guarantee a faster answer.
Stage 4: interpretation, confirmation and reporting
Clinically important findings undergo expert review and may need confirmation using an independent method. The report is then checked for consistency with the patient’s clinical presentation and formally approved.
Family-based testing may require additional analysis across relatives. Ask how results will be communicated and whether a consultation is available to explain the final report.
Why might a report be delayed?
Possible reasons include poor sample quality, repeat sampling, multiple family members, quality-control issues, confirmatory tests, difficult interpretation, laboratory holidays or transport to a partner facility.
A delay does not predict a positive or negative finding. If the quoted date passes, ask which stage your sample has reached and when the next status update is expected.
How to follow up effectively
Keep your accession number, the date the laboratory received the sample and the quoted turnaround time. When contacting the laboratory, ask whether the sample is in wet-lab processing, bioinformatics analysis or final clinical review.
For genuinely time-sensitive clinical cases, the referring specialist can ask whether validated expedited testing is offered. Such a service is not available everywhere.
Frequently asked questions
Does a longer wait indicate a serious finding?
No. Turnaround time reflects technical and operational factors and cannot reliably predict the outcome.
Can WES be expedited?
Some laboratories provide prioritized services. Confirm eligibility, validation, cost and the actual timetable directly with the provider.
Scientific resources for further reading
For case-specific advice and current laboratory requirements, consult our services or genetic counseling team.
