Comparison of genetic reports

When it is needed

If laboratories gave different answers or documents concern different participants and objects.

What we examine

Complete reports and their appendices.
Description of objects examined and participants.
Wording of relationship hypotheses and calculation results.

Materials to prepare

Both complete documents after transfer arrangements have been agreed.
Questions put to the providers and participant list.
Information about sample collection and identifiers.
Specific differences requiring explanation.

Sample questions

Do the results relate to the same participants and objects?
Are the relationship hypotheses tested the same?
Are the genetic systems examined and calculation approaches comparable?
Are differences explained by material contents or methods?
Which questions should be put to the providers to clarify discrepancies?

Build a set of questions →

How the work is carried out

Compare the briefs, participants and objects of the two examinations.
Check methodological and calculation assumptions behind differing conclusions.
Prepare an explanation of differences found and clarifying questions.

Result

A comparative analysis identifying agreements, substantive discrepancies and possible reasons for differences.

What affects the conclusions

Comparing documents is not repeat genotyping. Significant doubts about laboratory data may require a new examination of samples.

Frequently asked questions

Do two different percentages necessarily contradict one another?

No. The indicators may relate to different hypotheses, participants and statistical assumptions. They are compared together with the calculation conditions.

Can the correct report be selected from a single final page?

This is usually insufficient. Information about the materials, methods and examination process underlying the answer is needed.

Where to start when comparing two genetic reports

For a substantive comparison, first create two parallel columns: objects examined, participants identified and the question each provider tested. Only then move to numerical results. Documents may appear contradictory while actually addressing different relationship hypotheses.

It is useful to include a family diagram with coded participant identifiers and mark which relationships are accepted as calculation inputs. If one document checks direct kinship and the other a relationship through relatives, the final quantities cannot be compared as two answers to an identical brief. The genetic systems examined and completeness of the appendices provided are considered separately.

A comparison table identifies

The question posed and exact relationship hypotheses compared.

Participants and provenance of the samples examined.

Systems examined and availability of original results.

Names of statistical indicators, assumptions made and explanations of interpretation.

Differences explainable by the brief, and questions lacking sufficient data.

A likelihood ratio and a percentage estimate are not interchangeable names for one number. They are considered together with the hypotheses tested and calculation assumptions. A change in the final quantity does not yet show where the discrepancy arose: the set of objects examined, input data, model or presentation of the result. A comparative analysis must identify the particular cause or explicitly state which information is needed to check it. It does not replace repeat examination of samples if the question concerns the laboratory data themselves.