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Updated: Jul 4, 2026
Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
ADAMTS-13 activity and von Willebrand factor levels in methylene-blue photo-inactivated plasma processed by either
J del Río-Garma1, A Pereira, J L Arroyo
1Complexo Hospitalario, Ourense, Spain.
Background And Objectives:
Methylene blue photo-inactivated plasma (MBPIP) has been reported to be less effective than fresh-frozen plasma (FFP) in the treatment of thrombotic thrombocytopenic purpura, which suggests a reduced content of the von Willebrand factor metalloprotease ADAMTS-13 in MBPIP.
Materials And Methods:
ADAMTS-13 activity and von Willebrand factor antigen (vWF:Ag) levels were measured in plasma before and after photo-oxidation by either the Springe method or a commercial 'in house' system as well as in cryoprecipitate-poor plasma (CPP) and FFP (20 units each).
Results:
Levels of ADAMTS-13 activity in MBPIP processed by the Springe method or the commercial 'in house' system were comparable to one another and did not significantly differ from levels found in FFP [median (range): 114% (57-139%), 99% (74-123%), and 106% (70-130%), respectively]. ADAMTS-13 activity was significantly reduced in CPP [median (range): 87% (70-107%) as compared with FFP (P < 0.05). Levels of vWF:Ag decreased after photo-oxidation by both methods.
Conclusion:
In vitro ADAMTS-13 activity was conserved in MBPIP processed by the two photo-oxidation methods analysed and did not significantly differ from levels found in FFP.
Insights
Methylene blue photo-inactivated plasma (MBPIP) retains ADAMTS-13 activity, similar to fresh-frozen plasma (FFP). This finding is crucial for understanding MBPIP efficacy in treating thrombotic thrombocytopenic purpura.
Area of Science:
- Hematology
- Plasma Processing
- Biochemistry
Background:
- Methylene blue photo-inactivated plasma (MBPIP) efficacy in thrombotic thrombocytopenic purpura (TTP) is debated.
- Reduced efficacy may stem from lower levels of ADAMTS-13, a key enzyme in TTP pathogenesis.
Purpose of the Study:
- To quantify ADAMTS-13 activity in MBPIP after photo-oxidation.
- To compare ADAMTS-13 levels in MBPIP with fresh-frozen plasma (FFP) and cryoprecipitate-poor plasma (CPP).
Main Methods:
- ADAMTS-13 activity and von Willebrand factor antigen (vWF:Ag) were measured.
- Plasma samples underwent photo-oxidation using two distinct methods.
- Comparisons were made between MBPIP, FFP, and CPP.
Main Results:
- ADAMTS-13 activity in MBPIP was comparable to FFP across both photo-oxidation methods.
- ADAMTS-13 activity was significantly reduced in CPP compared to FFP.
- vWF:Ag levels decreased following photo-oxidation.
Conclusions:
- In vitro ADAMTS-13 activity is preserved in MBPIP.
- The photo-oxidation process, using the methods studied, does not significantly diminish ADAMTS-13 levels.
- These findings support the potential utility of MBPIP in TTP treatment by maintaining critical enzyme levels.
