Table 3.
Contingency tables and classification performance of Serum GFAP in detecting traumatic intracranial lesions on head CT.
| a. Isolated skull fractures excluded from intracranial lesions. | ||
|---|---|---|
|
| ||
| Table 3a. | CT positive | CT negative |
| GFAP positive >0.15 ng/ml | 17 | 71 |
| GFAP negative ≤0.15 ng/ml | 1 | 63 |
| Sensitivity | 94% (71-100) | |
| Specificity | 47% (38-56) | |
| NPV | 98% (90-100) | |
| PPV | 19% (12-29) | |
|
| ||
| b. Isolated skull fractures included with intracranial lesions. | ||
|
| ||
| Table 3b. | CT positive | CT negative |
|
| ||
| GFAP positive>0.15 ng/ml | 20 | 68 |
| GFAP negative ≤0.15 ng/ml | 1 | 63 |
| Sensitivity | 95% (74-100) | |
| Specificity | 48% (39-56) | |
| NPV | 98% (90-100) | |
| PPV | 22% (15-33) | |
|
| ||
| c. Patients presenting with a GCS 15. | ||
|
| ||
| Table 3c. | CT positive | CT negative |
|
| ||
| GFAP positive >0.15 ng/ml | 14 | 60 |
| GFAP negative ≤0.15 ng/ml | 1 | 60 |
| Sensitivity | 93% (66-100) | |
| Specificity | 50% (41-59) | |
| NPV | 98% (90-100) | |
| PPV | 19% (11-30) | |
CT = computed tomography; GFAP = glial fibrillary acidic protein; NPV = negative predictive value; PPV = positive predictive value