Back to results
US 5,506,112 AGranted
Reagent used for determining factor VIII activity
AssigneeImmuno Aktiengesellschaft
InventorsHartmut Lang, Berta Moritz, Manfred Oberreither, Olga Lukas
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeImmuno Aktiengesellschaft
InventorsHartmut Lang, Berta Moritz, Manfred Oberreither, Olga Lukas
Estimating the term…
To determine the factor VIII activity of a sample, the latter is reacted with a reagent containing thrombin, factor IXa.beta., phospholipids and calcium ions so as to form a factor VIIIa-factor IXa-phospholipid-calicum ion-containing complex. This complex is reacted with factor X so as to obtain activated factor X. The obtained factor Xa is reacted with chromogenic substrate so as to form a substance to be determined spectrophotometrically. Complex formation and activation of factor X are effected in one stage: The sample is mixed with a mixture of human thrombin, phospholipids, calcium ions, human factor IXa.beta., human factor X and, if desired, human factor XIa and human factor XIIa, as a complex-forming reagent.
A composition for determining factor VIII activity in a sample, which composition comprises, in a single reagent, from 0.05 to 5 U/ml of factor IXa.beta., from 0.01 to 10 U/ml of factor X, from 1 to 50 .mu.mol/ml of calcium ions, from 0.01 to 2.0 U/ml of thrombin, and from 0.01 to 100 nmol/ml of phospholipids.
A method of determining factor VIII activity in a sample comprising:
A method of determining proteins reacting with factor VIII, said proteins comprising protein C and ire co-factor protein S, factor VIII antibodies and factor VIII inhibiting proteins, by using a single reagent composition which comprises factor IXa.beta., factor X, calcium ions, thrombin and phospholipids, in amounts effective to measure factor VIII activity, wherein an excess amount of factor VIII is added to said sample and reacted therewith by inhibiting part of said factor VIII and leaving a remaining amount of factor VIII, said factor X is activated by said remaining amount of factor VIII, and said factor VIII is determined by measuring the amount of activated factor X.
Dependencies are inferred from the claim text.