Parentage Testing Health Article

Testing procedure

The laboratories that perform parentage testing are generally commercial facilities engaged in only parentage testing. The person seeking parentage testing contacts such a laboratory to receive instructions. Generally, the appointment for sample collection is scheduled at a local medical laboratory or clinic contracted by the testing laboratory. At the time of scheduling, the names, addresses, and telephone numbers of all persons to be tested, the date of birth or approximate age of the child(ren) to be tested, the preferred day and time for the sample collection, and the name and contact information of any attorney(s) involved is recorded. It is possible to schedule collections for different people in different locations at different times. The samples are all shipped to the testing laboratory to be analyzed simultaneously.

For testing with chain of custody, it is extremely important that everyone being tested is positively identified. For every adult person being tested, the social security number and a picture ID, such as a driver's license, passport, or state identification card is required, and for each child a birth certificate must be provided. Photographs and fingerprints of all persons may be taken at the time of sample collection. Strict chain of custody procedures must be followed, and all information and results are kept strictly confidential and are not released without proper prior authorization.

A small blood sample, usually from a finger prick, is collected from the mother, the child(ren), and alleged father(s). For newborns, the blood sample can be obtained from the umbilical cord at birth, or from a heel prick. Alternatively, cells from the inside of the mouth are collected with a buccal swab. It is also possible to arrange for prenatal testing to be performed on chorionic villi or precultured amniotic fluid cells.

Buccal swabs have become the specimen collection method of choice for DNA testing. The specimen is collected by gently stroking the inner facial cheek with the swab for 30 seconds. It is not necessary to fast before specimen collection, since buccal swab specimens are unaffected by foods, toothpaste, cigarettes, chewing tobacco, lipstick, or bacterial DNA. The collected buccal cells are still usable after years of storage. Buccal samples do not need to be refrigerated nor is immediate shipping to the laboratory required.

To extract DNA from the swab, the head of the swab is transferred to a small plastic tube containing a small amount (0.6 ml) of dilute sodium hydroxide solution (50 mM), and the stick is cut off to allow the tube to be closed (special buccal swabs with ejectable heads have recently become available). The tube is mixed and incubated for 5 min in boiling water, after which the swab

head is removed, and a few drops of a buffer (0.06 ml Tris-HCL, pH 8) are added.

For curiosity testing without chain of custody, kits can be obtained for home collection of cheek cells with buccal swabs. The samples are then sent by courier to the testing laboratory.

The fee for testing, with chain of custody, one alleged father and one child, usually with or without the mother, is $400–500, and about $150 is charged for each additional person tested. The level of the fee may also depend on the number of DNA loci or systems probed; generally six to 16 loci are analyzed. Most parentage testing firms require payment of a nonrefundable deposit of $100–150 to initiate the scheduling process; this deposit is applied toward the total fee. Payment may be made by major credit card, certified check, or money order, and is unlikely to be covered by medical insurance. In most cases, the local collection facility additionally charges a specimen collection fee, typically $15–40 per person. The fee for prenatal testing can be substantially higher. Testing without chain of custody can cost $280–400, depending on whether samples are collected at home or by a clinic. Curiosity testing may be performed on samples other than collected blood or buccal cells, such as cigarette butts, chewed gum, bloodstained or semenstained clothing, used condoms, plucked hair or electric razor debris, or Q-tips containing earwax; additional fees may apply for non-standard samples.