PMID- 10759006
OWN - NLM
STAT- MEDLINE
DCOM- 20000525
LR  - 20131121
IS  - 0957-5235 (Print)
IS  - 0957-5235 (Linking)
VI  - 11
IP  - 2
DP  - 2000 Mar
TI  - Monitoring unfractionated heparin therapy: relationship between eight anti-Xa 
      assays and a protamine titration assay.
PG  - 137-44
AB  - Several studies have demonstrated that heparin assays, such as anti-activated 
      factor X (anti-Xa) assays, can be successfully substituted for activated partial 
      thromboplastin time for heparin dosage monitoring. A number of different assays 
      are available and the relationship between results with different techniques is 
      largely unknown. The aim of the present study was to assess the relationship 
      between heparin assays by protamine titration and anti-Xa assays. Samples were 
      collected from 43 patients receiving unfractionated heparin (UFH). In each 
      sample, the heparin level was determined using a protamine titration assay and 
      eight commercially available anti-Xa assays. The mean heparin level by protamine 
      titration was 0.31 U/ml. Mean anti-Xa activity results ranged from 0.40 to 0.42 
      IU/ml for the three clotting-based assays, and from 0.32 to 0.40 IU/ml for five 
      chromogenic assays. Thus mean results of different anti-Xa assays varied by up to 
      30%. The range of anti-Xa activity equivalent, on average, to 0.2-0.4 U/ml by 
      protamine titration, considered to be the therapeutic range, was approximately 
      0.25-0.5 IU/ml, depending on the assay. The relationship between results of 
      clotting and chromogenic methods was similar irrespective of whether or not 
      warfarin-induced prolongation of international normalized ratios was present.
FAU - Kitchen, S
AU  - Kitchen S
AD  - Sheffield Haemophilia and Thrombosis Centre, Royal Hallamshire Hospital, UK. 
      steve.kitchen@csuh.nhs.uk
FAU - Theaker, J
AU  - Theaker J
FAU - Preston, F E
AU  - Preston FE
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - England
TA  - Blood Coagul Fibrinolysis
JT  - Blood coagulation & fibrinolysis : an international journal in haemostasis and 
      thrombosis
JID - 9102551
RN  - 0 (Antibodies)
RN  - 0 (Chromogenic Compounds)
RN  - 0 (Protamines)
RN  - 0 (Reagent Kits, Diagnostic)
RN  - 5Q7ZVV76EI (Warfarin)
RN  - 9005-49-6 (Heparin)
RN  - EC 3.4.21.6 (Factor Xa)
SB  - IM
MH  - Antibodies
MH  - Blood Coagulation Tests/methods/standards
MH  - Chromogenic Compounds
MH  - Factor Xa/immunology
MH  - Heparin/*blood/therapeutic use
MH  - Humans
MH  - International Normalized Ratio
MH  - Partial Thromboplastin Time
MH  - Protamines
MH  - Reagent Kits, Diagnostic
MH  - Reproducibility of Results
MH  - Sensitivity and Specificity
MH  - Spectrophotometry
MH  - Titrimetry/methods
MH  - Warfarin/pharmacology
EDAT- 2000/04/12 09:00
MHDA- 2000/06/08 09:00
CRDT- 2000/04/12 09:00
PHST- 2000/04/12 09:00 [pubmed]
PHST- 2000/06/08 09:00 [medline]
PHST- 2000/04/12 09:00 [entrez]
PST - ppublish
SO  - Blood Coagul Fibrinolysis. 2000 Mar;11(2):137-44.