In instances in which DNA samples are degraded, like if there are intense fires or all that remains are bone fragments, standard STR testing on those samples can be inadequate. When standard STR testing is done on highly degraded samples, the larger STR loci often drop out, and only partial DNA profiles are obtained. Partial DNA profiles can be a powerful tool, but the probability of a random match is larger than if a full profile was obtained. One method that has been developed to analyse degraded DNA samples is to use miniSTR technology. In the new approach, primers are specially designed to bind closer to the STR region.
In normal STR testing, the primers bind to longer sequences that contain the STR region within the segment. MiniSTR analysis, however, targets only the STR location, which results in a DNA product that is much smaller.
By placing the primers closer to the actual STR regions, there is a higher chance that successful amplification of this region will occur. Successful amplification of those STR regions can now occur, and more complete DNA profiles can be obtained.  The success that smaller PCR products produce a higher success rate with highly degraded samples was first reported in 1995, when miniSTR technology was used to identify victims of the Waco fire.