From: Direct access CT for suspicion of brain tumour: an analysis of referral pathways in a population-based patient group
Brain tumour
Total
Absent
Present
Freq
%
Odds ratio
95% CI
PPV
Red flag symptoms
1141
1109
92
32
3.7
5.73
2.21–14.84
2.8
Orange flag symptoms
728
723
99
5
0.7
1.34
0.38–4.68
Yellow flag symptoms
1069
1064
1
0.09
reference
0.5