In addition to standard hematology and chemistry and urinalysis, this depends on the serologic status and findings related to the disease activity. Most but not all patients are concordant (complements, Ds DNA antibodies, if positive, ESR, Gamma globulins). Ina addition SLE patients particularly those on steroids are subject to al the potential long term adverse events associated with this class of drugs (cardiovascular, lipids, bone etc) and Ned evaluation to address these issues at least at onset and then with some regularity thereafter. What is NOT needed is to repeatedly check ANA status. Once positive, then no need to repeat as the titre does not reflect disease activity as well as other more relevant measures.
As for frequency of checks. After the status is stable once every three months is adequate unless there are concerns regarding new activity. This interval also reflects appropriate monitoring of immunosuppressive agents once a stable long term dose has been determined.