About tattoos

[labrat1]

There are some threads here in which there are explanations about why tattoos are not allowed in certain studies (for medical reasons).
I think that it is because the dye that is used in tattoos can interfere with certain skin studies.

I am not sure if there are other aspects of tattoos that can "interfere" or "cross contaminate " with experimental medications.

However one thing I wonder about is, in cases in which tattoos can cause problems with a study's accurate results or may endanger the tattooed volunteer in some way, can a person get rid of his or her tattoos and then be medically-qualified for the study?

Of course since certain studies (that would restrict tattooed people) only are recruiting for a certain amount of time, a tattooed person may not have the right amount of time to get rid of his/her tattoos especially if it is a large tattoo or if a person has several tattoos. Tattoo removal can take several weeks of individual treatments (as far as I know).

But what if a tattooed person gets laser treatment or tattoo-removal surgery, will that remove the dye or whatever else from the person's skin so that s/he may qualify to participate in a "tattoo-rejecting" study?

Or, will only the visual part of the tattoo itself be removed and certain dyes still remain under the skin?

If a person has had tattoos in the distant past but has had them removed, would that person still be rejected from certain studies that do not allow tattoos? Are researchers cautious about any remaining dye in a formerly-tattooed person's skin?
I have heard of studies that reject tattooed persons but not "formerly tattooed" people.

Anyone know if there have been studies that reject people who are tattooed or who "ever have been" tattooed?
If so, then how can the researchers know for sure if an applicant rat has had tattoos in the past? It seems that if they cannot see the tattoos they would just ask the applicant if s/he has had tattoos anytime in the past. But is there any test to find that out? Can a doctor or dermatologist look at the skin and know? If a rat does not reveal that s/he has had tattoos would it eventually be found out if the study involves certain procedures?

Can a person who has a tattoo on his ankle do a study that involves testing the skin or on another part of his body (such as a back patch study or maybe a brain MRI)?