| Differentiating feature | Subarachnoid hemorrhage | Traumatic puncture |
| Number of RBCs in successive tubes | Constant | Decreases |
| Clotted blood | Absent | Present (if RBC count>250,000 cells per mL |
| Xanthchromia | Present (>12 hours after bleed) | Absent |
| Relative proportion of WBCs | Increased | Normal |
| RBC/hemosiderin-containing macrophages | Present | Absent |
| CSF protien | Elevated | Normal |
| D-dimer assay | Positive | Negative |
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