Rees et al reported an index that correlates with the intracerebral blood velocity as measured by transcranial Doppler ultrasonography. An increased blood velocity in the middle cerebral artery is associated with an increased risk for stroke in patients with sickle cell anemia. The authors are from King’s College and Evelina Children’s Hospital in London.


Patient selection: pediatric patients with sickle cell anemia with ages 2 to 16 years



(1) hemoglobin (units presumably g/dL)

(2) age

(3) serum AST (units presumably IU/L)


index = estimate for time-averaged mean of the maximum intracerebral blood velocity =

= 220 – (8 * (hemoglobin)) – (1.4 * (age)) + (0.4 * (AST))



• An index > 170 identifies a child who should have transcranial Doppler ultrasonography to measure intracerebral blood velocity.



• The test was found to be 100% sensitive. Specificity ranged from 58 to 73%.

• Performance would be affected by the AST assay.


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