What kind of tests are they? If you are using CLIA waived POC cups, then they would need the model number of the cup to make sure it is on the CLIA waived list. If you are using an analyzer, they will need the make and model of the machine your lab uses. Make sure this information is sent directly to the auditor, because for some reason, the PNI reviewers throw it away. (We sent that info over 50 times, and they still claimed it was never sent) As far as what records they want, you need the doctors order, the lab results, and the treatment plans and counseling notes in which the UAs are discussed with the patient. If your Dr order is exact, (e.g. if it says to test every 3 days) make sure the testing schedule meets exactly what the Dr order says. (We got burned on that one, our order said every 3 days, and we were recouped on the ones that did not exactly follow).
We recently just got out of our audit. (both retrospective, and prepayment review). The best advice I can give is make sure you send records within 45 days of the original remittance because you will not always receive the letter (some of ours took over 30 days to get to us). Also make sure you follow up directly with the PNI department on every claim. (This is tedious and takes forever, but worth it because that office makes tons of mistakes and claims to not have tons of records that they do have) If you are faxing records, do not send the records for more than one claim at a time. (Again the PNI office is easily confused) Finally, if you think they did not get it right appeal.
Hope this helps.