Guided review of the HbA2 result

Return to the adult outpatient result. The specimen is EDTA whole blood collected today, with no available transfusion, transplant, or gene-therapy history. The HPLC result is HbA 91.0%, HbA2 5.2%, HbF 1.0%, and no reportable variant peak. The local adult interval for HbA2 is 2.0 to 3.5%, but this interval and the retention-window assignment are method-specific.

The CBC shows microcytosis with an RBC count of 5.42 × 10^12/L, MCV 71 fL, and MCH 22.5 pg. Adult HbA2 above 3.5% with microcytosis supports beta-thalassemia carrier evaluation. The pattern does not prove a genotype, distinguish every delta-chain or alpha-chain influence, or exclude iron deficiency and other analytical influences. Review the chromatogram, CBC, and clinical context together before deciding the report wording.

The defensible next step is to inspect this HPLC chromatogram and verify the current analyzer, reagent, and software instructions for HbA2-window and modified-fraction limitations. If that HPLC review leaves the clinically consequential pattern unresolved, perform the locally validated CE follow-up; refer for molecular testing only for a defined remaining globin-gene sequence or copy-number question that the referral assay covers. The report can state that an elevated HbA2 fraction with microcytosis is compatible with carrier evaluation on this method. It should not name a genotype from this HPLC percentage alone. Make the limitation visible in the released interpretive language.