TABLE 2:

Patients with negative head CT findings and no aneurysms on angiography

Patient	Tube 1 (RBCs/mm³)	Tube 4 (RBCs/mm³)	% Change from Tube 1 to 4	Angiographic Result	Clinical Diagnosis
1	293	2	−99	Normal	None. Normal follow-up cerebral MRA.
2	6230	60	−99	Normal	Traumatic SAH
3	711	404	−43.2	Normal	Cocaineuse or migraine
4	2450	2100	−14.3	Normal	Sickle-cell disease
5	414,750	364,875	−12.0	Normal	None, normal follow-up cerebral MRA
6	117,600	105,400	−10.4	Normal	Varicella and cryptococcal meningitis (HIV+)
7	1634	1623	−0.7	Normal	Sickle-cell disease
8	65,363	68,750	5.2	Normal	None, normal follow-up cerebral angiography
9	33,525	36,425	8.7	Normal	None, normal follow-up cerebral angiography
10	120	149	24.2	Normal	Systemic lupus erythematosus and antiphospholipid antibody syndrome
11	69,090	91,035	31.8	Normal	None; patient lost to follow-up
12	992	1776	79.0	Normal	Migraine headache
13	37	119	220	Normal	Traumatic SAH
14	837	8330	895	Normal	Varicella encephalitis (HIV+)

Note.—Bold entries indicate cases in which the 25% threshold for clearing was met.