Table III.

Potential Indications and Strength of Recommendation^* for Hydroxyurea Therapy in Children with HbSS

Category	Indication	Strength of Recommendation
Acute vaso-occlusive	Frequent Painful Events Dactylitis Acute Chest Syndrome	Strong Strong Moderate
Laboratory markers of severity	Low Hb Concentration Low HbF Elevated WBC Elevated LDH	Weak Weak Weak Weak
Organ Dysfunction      Brain      Lungs      Renal	Elevated TCD velocities Silent MRI, MRA changes Stroke prophylaxis	Moderate Weak Moderate
	Hypoxemia Comorbid Asthma	Weak Weak
	Proteinuria	Weak
Miscellaneous	Sibling on hydroxyurea Parental Request	Weak Moderate

Hb indicates hemoglobin; HbF, hemoglobin F; WBC, white blood cell count; LDH, lactate dehydrogenase; TCD, transcranial Doppler ultrasound; MRI, magnetic resonance imaging; MRA, magnetic resonance angiography;

^*Strength of recommendation based on published data and expert opinion when data are unavailable (sibling on hydroxyurea, parental request)