Lumbar puncture, commonly performed to diagnose life-threatening central nervous system (CNS) conditions, sometimes is delayed or deferred in patients with coagulopathies because of concern that spinal hematoma might develop. Researchers retrospectively reviewed 83,000 lumbar punctures (in 64,000 patients, of whom 10,400 had coagulopathies) in a population-based Danish medical registry to evaluate this risk.

Thirty-day incidence of spinal hematoma was 0.20% in patients without coagulopathies and 0.23% in those with coagulopathies (i.e., platelet count <150×10⁹/L, international normalized ratio [INR] >1.4, or activated partial thromboplastin time [aPTT] >39 seconds). Risk did not increase significantly with rising severity of coagulopathy, procedural indication (i.e., infection, neurological condition, or hematological malignancy), or cumulative number of procedures. Among a subgroup of 1237 coagulopathic patients, 28% were taking anticoagulant or antiplatelet medications at the time of the procedure; none of these patients developed spinal hematoma.