Diagnosis of subarachnoid hemorrhage is usually established by computed tomographic scanning; however, in a few patients, lumbar puncture to examine the cerebrospinal fluid for erythrocytes and xanthochromia is necessary. Some authorities recommend delaying lumbar puncture by 12 hours following onset of symptoms to ensure sufficient time has elapsed for xanthochromia to develop. This recommendation is based on measuring xanthochromia by spectrophotometry. Our hypothesis was that very few hospital laboratories in the United States use this method.
To determine the percentage of hospital clinical laboratories that measure for xanthochromia using spectrophotometry.
Mail survey to 3500 hospital clinical laboratory directors (in collaboration with the College of American Pathologists). Surveys were mailed in January 2001 and the results tabulated 1 month later. Participation was voluntary.
Percentage of hospital clinical laboratories that use spectrophotometry versus visual inspection.
Of the 3500 laboratories surveyed, 2551 (72.9%) responded. Of these, 1944 (76.2%) indicated that they evaluated for xanthochromia. Of the 1952 laboratories that answered the question "How do you report your results?" 1947 (99.7%) reported using visual inspection.
When evaluating for xanthochromia in cerebrospinal fluid, nearly all hospital clinical laboratories in the United States use visual inspection. Given this current reality, the recommendation of delaying lumbar puncture by 12 hours needs to be reassessed.