Nested select using decode error

Hello,

I am a novice at SQL and especially decode clause. I am trying to get only lab test of "GLUCOSE" and I can't seem to get the syntax correct. I keep getting a missing expression error. If I take the second SELECT statement out, it runs great, but gives me all lab tests. Please help.

SELECT cci.CRITICALVALUESNOTIFICATION_201.patid, cci.CRITICALVALUESNOTIFICATION_201.key,
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 5,cci.CRITICALVALUESNOTIFICATION_201.data)) lab_test,
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 1,cci.CRITICALVALUESNOTIFICATION_201.data)) TimeLapseDate,
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 56,cci.CRITICALVALUESNOTIFICATION_201.data)) time_one,
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 57,cci.CRITICALVALUESNOTIFICATION_201.data)) time_two,
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 39,cci.CRITICALVALUESNOTIFICATION_201.data)) time_three,
cci.NAME_517.patid, cci.PATID_3592.patid, cci.SSN_518.patid
FROM cci.CRITICALVALUESNOTIFICATION_201, cci.NAME_517, cci.PATID_3592, cci.SSN_518
WHERE
(select patid from cci.CRITICALVALUESNOTIFICATION_201
WHERE (decode(cci.CRITICALVALUESNOTIFICATION_201.tag,5,) )
LIKE '%GLUCOSE%')
AND cci.CRITICALVALUESNOTIFICATION_201.patid = cci.NAME_517.patid AND
cci.CRITICALVALUESNOTIFICATION_201.patid = cci.PATID_3592.patid AND
cci.CRITICALVALUESNOTIFICATION_201.patid = cci.SSN_518.patid
GROUP by cci.CRITICALVALUESNOTIFICATION_201.patid, cci.CRITICALVALUESNOTIFICATION_201.key, cci.NAME_517.patid, cci.PATID_3592.patid, cci.SSN_518.patid