Modify the design of the CoSense device (Model C20112, currently cleared by the FDA for ETCO (end-tidal carbon monoxide) monitoring to improve accuracy and consistency under temperature conditions encountered in countries with high prevalence of SCD (Sickle Cell Disease).

Increase the temperature operating range of ETCO measurements to 5 to 45°C. The signal output-to-CO (carbon monoxide) concentration correlation of the CO sensor is dependent on temperature. The new algorithm will be a different approach because the current algorithm is at the limits of its capability. We will establish the new specifications by determining performance in a bench model under simulated temperature conditions. We will then determine the ability of the modified device to distinguish between SCD and healthy controls. During this initial testing, we will examine the validity of ETCO measurements under regulated room temperature in the hospital setting. We will enroll 20 subjects, 10 each in the SCD arm and control arm to determine the mean and variance of the ETCO values.

Inclusion Criteria:

• Parental / legal guardian consent
• Subject assent for participants ages 7 and above
• Male and female children ages 1-18 years old
• For Hb SS (Homozygous sickle cell anemia) subjects, hemoglobin baseline hemoglobin ≤10 g/dL based upon average hemoglobin value in past year

Exclusion Criteria:

• Subjects must not meet any of the following exclusion criteria to be considered eligible for study enrollment:
• Had a red blood cell transfusion within 8 weeks prior to enrollment
• Currently a primary smoker or was a primary smoker within 4 weeks prior to enrollment
• Exposed to second hand smoke within 24 hours prior to breath sample collections
• Have current upper respiratory infection or symptomatic asthma
• For healthy subjects, known to have the sickle cell trait by electrophoresis or genetic testing

A limitation of the data is the small number of subjects and that it was conducted under controlled circumstances in the clinic.