INTRODUCTION: Acute severe @entity10 is a common medical presentation, and a common area of diagnostic uncertainty. @entity510 ( @entity510 ) is the cause in a minority of @entity1 and has a high rate of morbidity and mortality. Therefore, its conclusive diagnosis with computed tomography (CT) or lumbar puncture (LP) is paramount. With advancement in imaging technology, emerging evidence now suggests that LP is no longer required for a subset of @entity1 as CT has 100% sensitivity in detecting @entity510 , when performed under specific conditions. OBJECTIVES: To assess the proportion of @entity1 with conclusive CSF xanthochromia results following a negative CT scan in suspected @entity510 to determine the diagnostic efficacy of LP. METHODS: CSF @entity648 and oxyhaemoglobin spectrophotometric absorbance data from all centres in a regional health board were identified for consecutive @entity1 over a 6-month period. Results were stratified as conclusive (positive or negative), or inconclusive according to national guidelines. RESULTS: 239 of 255 (93.7%) results were conclusive: 89.0% were negative (227 of 255). 4.7% of results were positive (12 of 255), revealing 4 @entity438 requiring treatment. 16 out of 255 (6.3%) samples were inconclusive, yielding 1 @entity439 requiring treatment. In the same period, there were 27 CT-positive cases of @entity510 . CONCLUSIONS: LP has a high diagnostic yield, eliminating the need for neurosurgical opinion or investigation in almost 90% of cases. The test is both cost and time efficient and subjects only a small number of @entity1 to the radiation and contrast risks of angiography.

Defending a traditional practice in the modern era: The use of lumbar puncture in the investigation of XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity510 :: ('MESH:D013345', 'Disease') :: ['SAH', 'Subarachnoid haemorrhage'] @entity648 :: ('MESH:D001663', 'Chemical') :: ['bilirubin'] @entity439 :: ('MESH:D000783', 'Disease') :: ['aneurysm'] @entity10 :: ('MESH:D006261', 'Disease') :: ['headache'] @entity438 :: ('MESH:D002532', 'Disease') :: ['cerebral aneurysms']
@entity510 :: (MESH:D013345,Disease) :: ['subarachnoid haemorrhage']
