The determination of the ratio of hemoglobin G compared to total hemoglobin present in a sample. The measurement may be expressed as a ratio or percentage. [ NCI ]. The trait is EFO_0009220 (Hemoglobin G Coushatta to Total Hemoglobin Ratio Measurement). Also known as: HBGCHTHB, Hemoglobin G Coushatta/Total Hemoglobin.