Paternity tests done by the PCR and RFLP methods return results that are normally expressed as "0% chance of parentage" or "better than a 99.0% chance of parentage". In other words, properly performed tests don't return results like "87.8%", and you should be immediately ask for a retest should your paternity test show any result that falls in between "0%" and "99.0%+".
Although a "99.0% chance of paternity" sounds pretty good at first, it only represents 1 out of 100 statistically- not nearly high enough to base actual paternity on. For real confidence of paternity, testing must be be to a level of 99.99%. This equates to only a 1-in-10,000 chance of misidentification.