Top 10 Frequently Asked Forensics Questions

Top 10 Frequently Asked Forensics Questions 


  1. Can the presence of blood, sperm or semen be detected on an item of clothing or other materials/objects? Yes. Testing can be performed to indicate the presence of blood, saliva, or semen in a sample. The test relies on the use of chemicals, which change color when coming in contact with blood, saliva, or semen.

  2. Are you able to get a DNA profile from urine? Yes. A profile can be obtained from urine. Over time bacteria in urine can degrade DNA, so fresh or frozen urine is the best type of sample to test.

  3. Can you test hair without the root? Yes. Instead of using nuclear DNA testing, we would use mitochondrial DNA testing. The mitochondrial genome is highly polymorphic or varies greatly from one person to another, making it useful for human identification. Because mitochondrial genes exist in high amounts within a cell they are very useful when analyzing samples that lack nuclear DNA.

  4. How much of an evidence sample is needed to obtain DNA results? This depends on the type and the condition of the sample. We specialize in extracting DNA from unusual and difficult forensic samples. Contact us to discuss the details involved with your case.

  5. I have a sample with a male/female mixture, but no male DNA profile was obtained from standard testing. Is there a way to obtain a male profile? Yes. Y-STR testingcan be used to obtain a male profile in these instances. However, a minimum amount of male DNA must be present. If a sample's minor component is male with the major component being female, then Y-STR testing may reveal a male DNA profile. Additionally, If there are multiple male contributors in a sample, Y-STR testing may help to differentiate the individual contributors.

  6. What kind of reference sample is required? For reference samples, we prefer buccal swabs or blood cards, but we will also accept whole blood. If you are sending whole blood, please use appropriate shipping materials to prevent breakage.

  7. How do I get a reference sample collected? DDC has the largest network of sample collection sites in North America. Contact us to schedule a sample collection at a local site within your community. We can also schedule sample collection at correctional facilities.

  8. How do I send a sample from another lab or hospital? The sample can be sent via courier to the following address: DDC Forensic Department, One DDC Way, Fairfield, OH 45014. We require all samples received by DDC to follow a strict chain of custody. Please contact us for this information

  9. Are your results compatible with the Combined DNA Index System (CODIS)? Yes. We test the 13-core CODIS loci that were set as standard markers for DNA testing by the FBI.

  10. How do I interpret a forensic DNA report? The forensics DNA report lists the samples tested and describes and provides the results based on a comparison of known and unknown evidence samples. The four possible interpretations for the results of a forensic DNA test are as follows: match, non-match, no DNA obtained, and inconclusive. A match means that the DNA profile obtained from the evidence sample is consistent with the DNA profile obtained from the known reference sample (ie. suspect). A non-match means that an individual's DNA profile is not consistent with the DNA profile obtained from the evidence sample. No DNA obtained means that we were unable to extract DNA from the evidence sample provided to us. An inconclusive result is obtained when there is insufficient DNA for comparison.