Flags indicating carrier status of class 2 or 3 KLF1 variants. Automated complete blood count (CBC): mean cell volume (MCV) and mean corpuscular hemoglobin (MCH) are low or at the low end of the normal range. Reticulocyte count (RTC) is high or at the high end of the normal range. ZnPP measured by hematofluorometer is high or at the high end of the normal range, with normal iron stores and absence of lead poisoning. HbA₂ and HbF are measured by high-performance liquid chromatography (HPLC) and are moderately increased or at the high end of the normal range. Lutheran antigens are measured by serology and are decreased but not completely absent; Indian antigen (CD44) is measured by flow cytometry and is reduced with normal expression of glycophorin A (CD235a). Weight of the arrows indicates the likelihood that a class 2 or 3 KLF1 variant is present; this increases when several flags are observed simultaneously.