Please list the patient's ID if he or she has an abnormal level of red blood cell and is followed at the outpatient clinic.
RBC < = 3.5 or RBC > = 6.0 means the patient has an abnormal level of red blood cell; 3.5 < RBC < 6.0 means the patient has a normal level of red blood cell; followed at the outpatient clinic refers to Admission = '-';
SELECT DISTINCT T1.ID FROM Patient AS T1 INNER JOIN Laboratory AS T2 ON T1.ID = T2.ID WHERE (T2.RBC <= 3.5 OR T2.RBC >= 6) AND T1.Admission = '-'