how long does it take to perform DNA testing?

small__2069420378Well, that depends on a number of factors:

  • The type of case –
    • samples that contain semen take longer to process for DNA than samples that do not because there are more steps involved in the process and because the samples yield not one but two DNA profiles (a male enriched profile (from semen) and a female enriched sample)
  • The number of evidence pieces submitted –
    • cases with lots and lots of evidence (usually homicide cases) take longer to process that cases with few samples
  • The throughput capacity of the lab –
    • how many people work in the lab? how many pieces of equipment are available? how efficiently does the laboratory work? These are all factors in throughput. Labs with automated processes that batch cases together and work in a factory-line approach have more throughput and usually better quality than laboratories that that do not automate analysis and process cases one at a time.
  • The case backlog –
    • how many cases are waiting for analysis? Depending on the laboratory, this could be a huge number. The NIJ reported that 168 laboratories that requested grant funding to alleviate DNA backlogs combined had over 100,000 cases waiting to be processed. Doing the math, that means that on average these labs had a backlog of 595 cases per lab in 2009. And with case submissions increasing each year (everyone wants DNA testing, right?), then the backlog similarly increases. That would mean that if the capacity of the lab was 300 cases per month, then the cases would be backlogged at least two months. If the lab’s capacity were 60 cases a month, then the backlog would be 10 months.

For more information, you can check out these sites:

The National Institute of Justice (NIJ)

The Office of the Inspector General’s audit of the FBI Crime Lab ~2 year backlog as of 2010

Office of Justice Programs (OJP) Fact Sheet


In the lab where I worked, we went from a large backlog to none by using increased staffing, automation, and grant funding to eliminate our DNA backlog. By the time I left, our total case turnaround time (from the time a case was submitted to our agency to the time we returned a final report) was 2-4 weeks depending on the type of case. With proper management and resources, it is possible for a crime laboratory to reduce their backlog and become effective. Sadly, many laboratories don’t have the budget, foresight, or management expertise to reduce their DNA backlogs. Instead, they request less than the number of staff needed and are slow to/refuse to update their processing paradigm to handle their case submissions.

But back to our original question…if an average case were submitted (say 5 samples) and it was started as soon as it reached the laboratory and people worked on it around the clock, then the case could be done in 2-3 days.




5 thoughts on “how long does it take to perform DNA testing?

      1. Well….crimes still take place in spec-fic books. Maybe something that would help writers figure out what would be plausible for the way forensics would work in a future world. Even just basic DNA stuff to help writers dealing with aliens and such. Seems like there has got to be some application….


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