you asked..
> I am billing oxygen for the first time today.  I have a new oxygen
> patient and some old ones to bill
> I am really nervous billing these b/c I am unsure of the CMN thing. 
 On the old ones that  has a CMN for the date of the recert is incorrect how do I fix this?



entering an o2 patient is same as everyone else
when you do the claim though several things
1. change the CLAIM TYPE FROM D TO O (oh)
that's for oxygen
2. complete claim as normal,, if you have the cmn there , when it asks to attach a cmn answer yes, and select the o2 cmn (484.3 i think)
answer the questions,, you will see in the first field the cmn type
1 new 2 revised 3 recert
and below are dates,, you enter all cmn dates as YYYYMMDD example
20090626

3. to update a cmn,, you select the patient on the do claims (transaction) screen where all the patients are listed, then click the UPDATE/PRINT CMNS button
if the patient has an o2 claim, it will appear when you click the O2 CMN BUTTON
if they dont have one, you can go back into the claim and answer Y to transmit, make sure CLAIM TYPE IS O and answer Y to attach cmn,, see #2 above

4. if the UPDATE/PRINT CMNS shows a cmn, select it, click  change and modify the
CMN TYPE TO a 2 for reviesed or 3 for recent, complete the dates  and it will be resent with the claim,,

cmns and cliams are matched by patient and transaction #