Extracts the first test only per patient
SurveilFirstTest(dataframe, HospNum_Id, Endo_ResultPerformed)
dataframe | dataframe |
---|---|
HospNum_Id | Patient ID |
Endo_ResultPerformed | Date of the Endoscopy |
dd<-SurveilFirstTest(Myendo,'HospitalNumber', 'Dateofprocedure')