What Causes Hair DNA Tests to Fail or Produce Inconclusive Results?
Hair DNA tests may produce inconclusive results when the specimens are improperly collected, stored, or exposed to conditions that accelerate DNA degradation. In our experience coordinating DNA testing cases, one of the most common mistakes people make is storing hair follicle samples inside plastic bags, such as Ziploc bags. Plastic bags can trap moisture, which may damage the specimens over time and reduce the likelihood that the laboratory will be able to recover a usable DNA profile.
Exposure to bleach, liquids, excessive heat, or prolonged storage can also affect the quality of the hair samples. The longer a specimen is stored before testing, the greater the risk that degradation may occur.
For this reason, we generally recommend collecting hair follicle samples as soon as possible and submitting them for testing without unnecessary delay. Hair samples should be kept at room temperature and stored in a dry environment to minimize the risk of moisture buildup.
Whenever possible, collecting the samples properly and submitting them promptly provides the best opportunity for the laboratory to develop a usable DNA profile.
Not sure whether additional hair samples are available or whether another forensic specimen may be a better option? Contact IDTO DNA at 888-204-0583 to speak with one of our DNA consultants before submitting additional samples.
What Are the Most Common Reasons Hair DNA Tests Fail?
Below are some of the most common reasons hair follicle samples fail to produce a complete DNA profile.
- Storage mishandling
- No root bulb is attached to the hair follicles
- Samples exposed to moisture
- DNA dedgradation over time
- Sample contamination
Why Is Cheek Swab DNA Testing Preferred?
In our experience, hair DNA testing is generally considered when a standard cheek swab collection is no longer possible. Whenever participants are available, cheek swab DNA testing remains the preferred method because it offers the highest probability of obtaining a complete DNA profile. Learn more about our Hair DNA Testing services and available testing options
Can Hair Without the Root Be Used for DNA Testing?
No. Hair strands without the root generally cannot be used for standard relationship DNA testing because the laboratory relies on the cells attached to the hair root to develop a complete DNA profile. Hair shafts alone do not typically contain sufficient nuclear DNA for paternity, sibling, or grandparent DNA analysis.
In most cases, the laboratory recommends submitting approximately 8 to 10 hair follicle samples with intact roots to increase the likelihood of producing a usable DNA profile. Whenever possible, the samples should be freshly collected and properly stored to help preserve their quality.
What Happens If a Hair DNA Test Fails?
When the hair follicle samples submitted to the laboratory are unable to produce a complete DNA profile, one of our DNA consultants will contact you to explain the laboratory’s findings and discuss the available options.
Option 1
The first option is to submit an additional set of specimens. Depending on your circumstances, this may involve providing another set of hair follicle samples or submitting an alternative forensic specimen, such as a toothbrush or earwax sample. Please note that additional laboratory DNA testing fees may apply when new samples are submitted for analysis.
Option 2.
When no additional samples are available, the second option is for the laboratory to close the case and issue a noncompliance report. A copy of the report will be mailed to you, and an additional copy will be sent to your email for your records.
In our experience, collecting fresh specimens and submitting them as soon as possible provides the best opportunity for obtaining a usable DNA profile.
How Often Are Hair DNA Tests Wrong?
Hair DNA tests themselves are not inherently inaccurate. The challenge is obtaining sufficient DNA from the submitted specimens. When a usable DNA profile is developed, the same genetic markers used in conventional DNA testing are analyzed.
Can Hairbrush Samples Be Used for DNA Testing?
Yes. Hairbrush samples may be used for DNA testing, provided that hair strands with intact roots are present. However, it is important to understand how the laboratory processes these specimens.
When a hairbrush is submitted, the laboratory will typically select approximately 8 to 10 hair follicle samples from the brush for analysis. If the selected hairs are unable to produce a complete DNA profile, you will be given the option of submitting additional specimens or allowing the laboratory to close the case and issue a noncompliance report documenting its findings.
In some situations, the laboratory may be able to analyze another set of hair follicle samples from the same brush. Alternatively, other forensic specimens may be considered if they are available. Additional laboratory fees may apply when new samples are submitted for analysis.
Please note that you may request the return of the hairbrush after testing has been completed. Return shipping fees may apply.
Does Hair Dye Affect DNA Testing?
No. Hair dye generally does not affect the root bulb portion of the hair strand, which is the part the laboratory uses to extract DNA and develop a DNA profile. Hair dye primarily affects the hair shaft and typically does not penetrate the root bulb where the cells used for DNA analysis are located.
For this reason, properly collected hair follicle samples with intact roots can still be suitable for DNA testing, even if the hair has been dyed.
Not sure whether your hair samples are suitable for DNA testing? Contact IDTO DNA at 888-204-0583 to speak with one of our DNA consultants. We can help you determine whether hair follicle samples or another specimen type may provide the best opportunity for obtaining a usable DNA profile.
