Hemophilia Testing Algorithm Symptomatic male Hemophilia A Hemophilia B F8A / Coagulation Factor VIII F_9 / Coagulation Factor IX Activity Assay, Plasma Activity Assay, Plasma Activity decreased? Activity decreased? YES YES Hemophilia A diagnosis ■ Vitamin K antagonist (ie, warfarin) ■ Child/adolescent? NO F8 genetic testing has been performed on a family member and the specific mutation is known? YES NO YES NO ■ Retest when >4 weeks after antagonist treatment is complete ■ Adjust decreased activity levels for age ■ If known mutation is an Intron 1 Inversion Severe hemophilia: Moderate/mild If the activity assays mutation, order F81B / Hemophilia A activity <1% hemophilia: are normal, consider an F8 Gene, Intron 1 Inversion Known activity 1% alternate bleeding disorder: Mutation, Whole Blood* to 55% ALBLD / Bleeding Diathesis NO Is activity still decreased? YES Hemophilia B diagnosis ■ If known mutation is an Intron 22 Profile, Limited, Plasma inversion, order F822B / Hemophilia A F8INV / Hemophilia A F9 genetic testing has been performed F8 Gene, Intron 22 Inversion Known F8 Gene, Intron 1 and on a family member and the specific Mutation, Whole Blood* 22 Inversion Mutation mutation is known? ■ If known mutation is a point mutation Analysis, Whole Blood or deletion/duplication, contact a Laboratory Genetic Counselor to discuss YES NO targeted familial mutation testing FIXKM / Hemophilia B, NGSF9 / Hemophilia B, Inversion found Inversion not found F9 Gene Known F9 Gene, Next-Generation Mutation, Whole Blood* Sequencing, Varies F8NGS / Hemophilia A, F8 Gene, Next-Generation Sequencing, Varies Mutation found Mutation not found Contact a Laboratory Genetic Counselor Mutation found Mutation not found to discuss send-out for large deletion/ duplication analysis of F9 gene Contact a Laboratory Genetic Counselor to discuss send-out testing for large deletion/duplication analysis of F8 gene** *Send copy of known familial mutation with sample for testing to be performed **If all testing is normal, consider possibility that family member has alternate bleeding disorder © Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. 12/2019.