Biomarker for acute ischemic stroke shows promise

This one takes 24 hours to determine you had an ischemic strokewhat about a bleeder?
And detecting acrolein can be done in 30 minutes in an earlier post of mine.
Or measure levels of a brain chemical called glutamate within an hour in an earlier post of mine.
Acrolin:
http://oc1dean.blogspot.com/2011/07/detecting-possible-stroke-biomarker-in.html
Glutamate:
http://www.webmd.com/stroke/news/20110929/blood-test-may-help-spot-stroke

Biomarker here: http://www.theheart.org/article/1294591.do
Increased NR2 peptide levels accurately identify patients with acute ischemic stroke within 24 hours of symptom onset and correlate with neuroimaging findings, results of a pilot study suggest [1].

The NR2 peptide may improve the diagnosis and management of patients presenting with acute stroke symptoms, the researchers conclude.

"I think this can be a very meaningful test," said Dr Kerstin Bettermann (Penn State College of Medicine, Hershey), who reported the results here at the American Neurological Association 2011 Annual Meeting.

The NR2 peptide, a proteolytic breakdown product of the brain-specific NMDA receptor, is an indicator of damage to the blood-brain barrier that follows an acute cerebral ischemic event. The peptide is rapidly released into the bloodstream during acute brain ischemia.

The pilot study involved 50 adults with acute ischemic stroke confirmed by either head CT or brain MRI within 24 hours of symptom onset and 102 age- and gender-matched controls. The control group consisted of 26 healthy adults, 48 adults with vascular risk factors including diabetes and hypertension but no history of stroke or transient ischemic attack (TIA), and 28 adults with "stroke mimics" such as migraine, meningitis, palsies, and intracranial hemorrhage due to aneurysm rupture. NR2 peptide levels were measured within 24 hours from symptom onset.

Healthy controls and those with vascular risk factors had NR2 peptide concentrations <0.25 and <0.4 mcg/L, respectively, while those with stroke mimics had mean concentrations of 0.5 mcg/L.

In contrast, acute ischemic stroke patients had concentrations that were significantly higher (>0.5 mcg/L) compared with all control groups (p<0.0001). The highest NR2 peptide levels were seen within 12 hours, with peak concentrations at one to three hours after symptom onset (mean 25.44 mcg/L; range 1.46-86.70 mcg/L).

At a cutoff point of 0.5 mcg/L, the NR2 peptide test had high diagnostic sensitivity, indicating true positive diagnosis of ischemic stroke, high specificity, meaning the correct identification of stroke mimics, and positive and negative predictive values, signifying the proportion of subjects with positive/negative NR2 peptide elevations who are correctly diagnosed.

Test performance at a cutoff point of 0.5 mcg/L

Performance measure	% (95% CI)
Sensitivity	98 (89.4-99.9)
Specificity	86.3 (78-92.3)
Positive predictive value	78 (65.5-87.3)
Negative predictive value	98.9 (93.9-99.9)

The results also suggested a significant correlation between NR2 peptide levels and cortical lesion size (<200 cc). However, researchers say this finding requires further validation.

"This is a simple test to do, and the preliminary data look excellent," Bettermann said. "The real key now is to validate it in a larger study population and we have applied to [the National Institutes of Health] NIH for funds to do this. . . . Ideally this is something you could do in the emergency room or even in the ambulance; it could be developed into a point-of-care finger stick test."

It might also be useful not only for stroke, but for transient ischemic attack. "In another study, we have some preliminary data that look promising," Bettermann noted.