I think that it just gives the name of his rank at the last muster.
For example, John Keeton of Company I, 4th Arkansas died of disease in 1863. Ancestry just notes his "rank out" as private, which is correct. The actual service record, however, gives the details of service and death.
What soldier are you looking into? Nearly all CSA records and some Union service records are available online at fold3.com with a subscription. I'd be glad to see if they have his record.
-Scott