[Previously posted over here]
When I did my elective in South Africa we used to diagnose TB in the casualty dept. by sticking a cannula in the pleural effusion, sucking out some fluid, diluting it 1:9 with tap water and then dropping some on a urine dipstick. If you had 3+ of protein you had TB.
These guys did a somewhat similar idea with CSF samples looking for blood.
Absolutely cracking idea for a study.
Few problems (which they acknowledge)
– they looked at whatever CSF came into the lab that wasn’t grossly xanthocromic. Lots of these weren’t for SAH and indeed they don’t tell us how many were +ve for SAH
– it’s not clear if time delay to testing would be relevant. They tell us it was within a week but it’s not clear if it’s significant
They found moderate (about 90%) sensitivity and specificity in the 50s. Not good enough for SAH in my opinion. Gold standard was spectrophotometery here, which is better than a guy in a lab holding up the tube against a sheet of white paper deciding if it looks a bit yellow or not.
Worth some follow up study
PS the Werstern Journal of Emergency Medicine has some nice stuff but
doesn’t appear to be on PubMed? the WJEM can be found free full text at pub med central which has a couple of open access EM journals