Laboratory identification of factor inhibitors: an update

Area of Science:

• Hematology
• Immunology
• Clinical Pathology

Background:

• Coagulation factor inhibitors are antibodies targeting pro-coagulant plasma proteins.
• Most commonly, inhibitors target factor VIII (FVIII), leading to inherited or acquired hemophilia A (HA).
• Clinical suspicion arises from unexplained bleeding or treatment failure in hemophiliacs.

Purpose of the Study:

• To overview the laboratory investigation of coagulation factor inhibitors.
• To review cross-laboratory inhibitor studies and evidence on inhibitor formation related to therapy types.

Main Methods:

• Systematic laboratory approach to identify inhibitors, excluding other causes of prolonged clotting times (APTT, PT).
• Utilizing coagulation factor inhibitor studies, including the Bethesda assay, to quantify inhibitor titre.
• Reviewing recent cross-laboratory studies and therapeutic evidence.

Main Results:

• Accurate identification of inhibitors requires excluding other causes of prolonged APTT/PT.
• The Bethesda assay quantifies inhibitor titre, guiding therapeutic decisions.
• Recent studies provide insights into inhibitor formation based on therapy.

Conclusions:

• Laboratory diagnosis of coagulation factor inhibitors is critical for managing bleeding disorders.
• Inhibitor titre measurement guides treatment efficacy.
• Understanding differential inhibitor formation is key for optimizing hemophilia care.