Rapid differentiation of subarachnoid hemorrhage from traumatic lumbar puncture using the D-dimer assay.

The D-dimer assay of 40 cerebral spinal fluid (CSF) samples accurately differentiated subarachnoid hemorrhage (SAH) from traumatic lumbar puncture. The D-dimer assay was positive in all six patients with subarachnoid hemorrhage. Negative D-dimer values were obtained in control groups of 14 patients with hemorrhagic CSF secondary to traumatic lumbar puncture (LP) and in 20 patients with normal CSF. The D-dimer assay proved to be a better test than xanthochromia or the decline in erythrocyte count in sequentially collected tubes in differentiating subarachnoid hemorrhage from traumatic LP.