Many minors have normal hemoglobin levels. This is why many minors never learn their status. It may be a milder mutation, a higher production of fetal hemoglobin than normal or the presence of an alpha thal deletion that explains why. You will still have certain characteristics of thal minors that can be detected in a CBC, such as a high RBC, low MCV and MCH and the visual observation of some pale small red blood cells. A hemoglobin electrophoresis would reveal a higher than normal HbA2 (unless an alpha deletion is also present) and a measurable amount of fetal hemoglobin, HbF. Even with a normal level Hb, some minors still have some symptoms, as part of the total is HbF, which is not as efficient at delivering oxygen to the body, so the Hb can look normal but the minor may still have some fatigue and tiredness.