When an alternative sample is considered
Families turn to alternative samples when a participant has passed away, lives far away and cannot be reached, or when a personal item is the only link to a person. Items such as a toothbrush, an envelope or stamp someone licked, hair with the root attached, or a used cup may carry enough DNA for testing.
Success is not certain. The amount and quality of DNA on an item varies greatly, and age, handling and storage all play a role. A sample may need to be screened before a full relationship test can go ahead.
Handling items so they stay useful
How an item is stored after it is found matters. Moisture and heat break down DNA, and plastic bags can trap humidity. Paper envelopes are usually better. Handle items as little as possible, ideally with clean gloves, and avoid touching surfaces likely to hold DNA.
- Store items in a clean paper envelope
- Keep items cool and dry
- Handle as little as possible
- Note who used the item and when
Limits worth understanding
Items shared by several people, such as a hairbrush used by a whole family, may hold mixed DNA. Hair that has fallen out naturally often lacks the root needed for standard testing. Because the origin of a personal item cannot be documented like a supervised swab, alternative samples are usually suited to private peace of mind rather than legal use.
How Alternative Sample DNA Testing works, step by step
- 01
Describe the item
Explain what it is, who used it and how it has been stored.
- 02
Package carefully
Place the item in a paper envelope and keep it cool and dry.
- 03
Screening
The laboratory checks whether usable DNA can be recovered.
- 04
Comparison
If successful, the profile is compared with the other participants.
Questions about Alternative Sample DNA Testing
Will any toothbrush work?
Not always. Results depend on how much DNA remains and whether the brush was used by only one person.
Can alternative samples be used in court?
Usually not, because the origin of a personal item cannot be documented the way a supervised collection can.
