This is a 35-year-old female who was recently noted to have breast mass and workup revealed strong family history of cancer. Workup CBC revealed abnormal findings as below:

Component    Value          Ref Range & Units   
WBC               5.3            3.5 - 11.0 10*3/uL  
RBC                5.52 (H)     3.88 - 5.26 10*6/uL   
Hemoglobin     11.7           11.5 - 15.5 g/dL  
Hematocrit       36.1          36 - 47 %   
MCV               65.4 (L)      81 - 99 fL   
MCH               21.2 (L)      26 - 33 pg   
MCHC             32.4          32 - 35 g/dL   
RBCW            15.4 (H)     <15.0 %   
Platelet Cnt     350           150 - 450 10*3/uL 

Learning points:

1. The findings below are characteristic of a beta-thalassemia trait with elevated total HbA2 (6%) and elevated F (2.8%).
2. Elevated RBC count with microcytosis supports thalassemia in this case. In iron deficiency, RBC count would be low.
3. Notably there is a variant HbA2 called HbA2 prime in this case which elutes as 4.53 minutes separate from HbA2 and may be missed in the calculation of total HbA2. This variant is a benign delta chain variant frequently seen in the African-American population.