For all patients with normal uric acid (UA), what is the average UA index based on their latest laboratory examination result?
uric acid (UA) with normal range refers to UA < 8.0 and SEX = 'M' or UA < 6.5 and SEX = 'F'; average UA index refers to AVG(UA)
SELECT AVG(T2.UA) FROM Patient AS T1 INNER JOIN Laboratory AS T2 ON T1.ID = T2.ID WHERE (T2.UA > 6.5 AND T1.SEX = 'F') OR (T2.UA > 8.0 AND T1.SEX = 'M') AND T2.Date = ( SELECT MAX(Date) FROM Laboratory )