Oklahoma State University Center for Health Sciences
Oklahoma State University Center for Health Sciences

Reports

Due to the science behind DNA testing and in order to comply with AABB standards, reports must be worded in a particular way that is not always easily understood. Wording on the report will depend on the relationship being tested; refer to the type of relationship listed below for specific wording. 

All reports will include:

  • Conclusion
    • “cannot be excluded” – while DNA testing results in high probabilities that a tested relationship is a true biological relationship, the probability will only approach 100%. A probability of >99% is strong enough evidence in support of a relationship that a judge will order child support or even conviction in a criminal case. In immigration cases a 99.5% probability is accepted as proof of relationship unless there are other circumstances that deny that relationship.
    • “excluded” – the DNA testing results do not support the relationship. The probability will be 0.
    • For relationships other than parentage, see the section below for specific wording.
  • Data table with a list of DNA genetic markers that have been tested and their allele designations.
    • A genetic marker is referred to as a locus. This locus is like an address for the marker’s location on a particular chromosome.
    • DNA testing uses Short Tandem Repeats (STRs) that are a sequence of DNA at a particular locus. These short sequences are repeated numerous times along a stretch of DNA. An allele number the different number of copies of this repeat. Alleles vary from person to person but are inherited from our parents, one from each parent. If an individual received the same allele from both parents, there will be only one number for that locus. Certain alleles are more frequent in different populations so you will see in your report that we have used the alleged parent’s race to base our calculations upon.
  • Combined Relationship Index (CRI) – A Relationship Index (RI) is calculated for each genetic marker in the data table. This number is associated with the statistical strength of that marker in favor of or against the relationship being tested. To calculate the CRI, all individual RIs are multiplied together. This number will be at least 100 if the alleged relationship is strongly supported by the test results. It will be 0 if the relationship is excluded.
  • Probability of Relatedness – The CRI is used to calculate the probability that the tested alleged individual is the true biological relative versus all other individuals in a given population. See “Conclusion” above.
  • The race used for the calculations will be indicated. This race is the one that was provided by the alleged parent, grandparent or aunt/uncle when they completed the consent form. The race of the alleged and the known parent may be different, but since calculations are performed using the frequency of the allele that might have been passed from the alleged relation, the race of the alleged parent is used. The race of General Population may be used if the race is unknown to the lab, when participants in relationships other than parentage provide different race, when a database for a particular race is not available, or or when dealing with forensic samples.

    Parentage (Paternity and Maternity)

    Paternity and maternity testing will typically be reported as either “cannot be excluded” or as “excluded.”

  • If your report contains the statement, “…[name] cannot be excluded as the biological father/mother of [child’s name]”, this means that the genetic evidence indicates that there is evidence that the tested alleged parent is the biological parent of the tested child. The goal of the testing is to produce a CRI of at least 100 and a probability of at least 99%. If you are testing two children and the CRI and probability are higher for one of the children, it only means that the genetic markers are less frequent in a particular population, making the statistical calculation of the CRI a larger number; it does not mean that it is more likely that one child is the biological child of an alleged parent.
  • If your report contains the statement, “…[name] is excluded as the biological father/mother of [child’s name]”, this means that there is no parent-to-child biological relationship between the tested alleged parent and the tested child. The CRI will be 0 and the Probability will be 0%.

First Degree Relatives: Full Siblings

Full siblings is a first degree relationship similar to paternity and maternity but, due to the reduced likelihood of the same allele being passed from parents of two different children (For example, there is a 25% chance that two true siblings will not share any allele(s) at a given locus.  A true parent will always share at least one allele with their child.), the results of a full sibling test are not as straightforward as a parentage test.

  • If your report contains the statement “…the relationship is highly likely…”, the CRI will be greater than 50.  The statement means that the genetic evidence significantly favors the probability that the tested participants are full siblings.
  • If your report contains the statement “…the relationship is likely…” , the CRI will be between 20 and 30. The statement means that the genetic evidence favors the probability that the tested participants are full siblings but that further testing or adding other test participants* may increase the likelihood of the relationship.
  • If your report contains the statement “..the results support the relationship…”, the CRI will be between 10 and 20. The statement means that the tested participants may be full siblings, but further testing or adding other test participants* is strongly suggested.
  • If your report contains the statement “…it is uncertain that [name] and [name] are first degree relatives…”, the CRI will be between 0.1 and 10. This is an intermediate area in which it is unable to determine whether the tested participants could be full siblings. Further testing or adding other test participants* is strongly suggested.
  • If your report contains the statement “…it is unlikely that [name] and [name] are related as first degree relatives”, the CRI will be less than 0.1. The statement means that there is little or no genetic evidence that the tested participants are full siblings.

*Other test participants may include parents, other siblings, or other known relations.

Second Degree Relatives: Half Siblings, Uncle/Aunt Or Grandparentage

Half siblings, avuncular (uncle/aunt) and grandparents are not direct relationships like that of parentage or full siblings. Due to the degree of separation in the relationship, it is strongly recommended to include a parent who is directly related to one or both participants.

For example, if siblings are being tested, a parent of one or both of the siblings will increase the likelihood of a compelling result. Or if a grandparentage is in question, the known parent should be included.

  • If your report contains the statement “…the relationship is highly likely…”, the CRI is greater than or equal to 100.  The statement means that the genetic evidence significantly favors the probability that the tested participants share the biological relationship that was tested.
  • If your report contains the statement “…the relationship is likely…” , the CRI is between 50 and 99.99. The statement means that the genetic evidence favors the probability that the tested participants share the biological relationship that was tested.
  • If your report contains the statement “..the results support the relationship…”, the CRI is between 20 and 50. The statement indicates that the tested participants may share the biological relationship that was tested. It is strongly recommended to include a parent who is directly related to one or both participants to improve the probability of the relationship.
  • If your report contains the statement “…it is uncertain that [name] and [name] are first degree relatives…”, the CRI is less than 20. This is an intermediate area in which the results are unable to determine whether the tested participants share the biological relationship that was tested. The lower the CRI value, the less likely it is that the tested participants share the relationship. It is strongly recommended to include a parent who is directly related to one or both participants to improve the probability of the relationship.

Y-STR Male Lineage

The results of Y-STR testing will be reported as either “consistent” or “not consistent.”

  • If your report contains the statement “The DNA profile produced from the sample labeled as [name] is consistent with the profile produced from the sample labeled a [name].”, the tested participants are likely to be from the same male lineage. If testing two brothers, this can indicate that they share the same father. If testing two samples that are believed to have come from the same individual male, the Y-STR profiles are the same.
  • If your report contains the statement “The DNA profile produced from the sample labeled as [name] is not consistent with the profile produced from the sample labeled as [name].”  This means that the two participants do not come from the same male lineage or that the two samples believed to have come from the same male do not originate from the same male source
OSU-CHS on Facebook OSU-CHS on Twitter OSU-CHS on Foursquare OSU Medicine on YouTube Google+