PMID- 9684794
OWN - NLM
STAT- MEDLINE
DCOM- 19981029
LR  - 20041117
IS  - 0340-6245 (Print)
IS  - 0340-6245 (Linking)
VI  - 80
IP  - 1
DP  - 1998 Jul
TI  - Monitoring heparin therapy using activated partial thromboplastin time--results 
      of a multicenter trial establishing the therapeutic range for SILIMAT, a reagent 
      with high sensitivity to heparin.
PG  - 104-8
AB  - APTT is widely used for laboratory monitoring of treatment with unfractionated 
      heparin (UFH). However, since its sensitivity to heparin varies significantly 
      from one reagent to another, the therapeutic range had to be defined for each 
      brand of APTT reagent. As an example, SILIMAT (bio-Merieux) is a new APTT reagent 
      containing rabbit brain phospholipids and micronized silica as an activator. 
      Since its high sensitivity to heparin has been previously reported, a multicenter 
      trial was carried out in an attempt to define the therapeutic range of APTT 
      performed using this new reagent. For that purpose, 170 blood samples drawn for 
      routine coagulation testing from 170 different patients treated with UFH were 
      analyzed. A single batch of two different APTT reagents were used on KC10 
      coagulometers: SILIMAT and Automated APTT (Organon-Teknika) whereas the anti-Xa 
      activity was evaluated by a chromogenic substrate-based assay. The same 
      methodology was used in all the centers. In order to obtain a plasma anti-Xa 
      activity within the therapeutic range i.e. between 0.30 and 0.70 IU/ml, the APTT 
      ratios were found between 1.90 and 5.40 for SILIMAT, which corresponded to 
      clotting times of the patients plasma between 63 and 178 s. The APTT ratios were 
      significantly lower when evaluated using Automated APTT (between 1.70 and 4.10), 
      with clotting times between 53 and 127 s. In addition, a good correlation was 
      found between the Anti-Xa activity and APTT for both reagents (r > 0.65). 
      However, it is not possible to make recommendations regarding the therapeutic 
      ranges without restrictions. Although about 70% of the patients with an anti-Xa 
      activity between 0.30 and 0.70 IU/ml had an APTT in the above defined ranges, the 
      degree of concordance between the two assays is not absolute. Actually more than 
      30% of the patients had discordant anti-Xa activity and APTT and more than a 
      quarter of the patients included in the above defined therapeutic range for APTT 
      had an anti-Xa activity outside the 0.30-0.70 IU/ml range, whatever the reagent 
      used. In conclusion, to define the therapeutic ranges of APTT using the 
      recommended method is practicable but some critical points could be raised, 
      suggesting that a better method is awaited in order to improve the 
      standardization.
FAU - Toulon, P
AU  - Toulon P
AD  - Laboratoires d'Hematologie, Hopital Cochin, Paris, France.
FAU - Boutiere, B
AU  - Boutiere B
FAU - Horellou, M H
AU  - Horellou MH
FAU - Trzeciak, M C
AU  - Trzeciak MC
FAU - Samama, M M
AU  - Samama MM
LA  - eng
PT  - Clinical Trial
PT  - Controlled Clinical Trial
PT  - Journal Article
PT  - Multicenter Study
PL  - Germany
TA  - Thromb Haemost
JT  - Thrombosis and haemostasis
JID - 7608063
RN  - 0 (Drug Combinations)
RN  - 0 (Indicators and Reagents)
RN  - 0 (Phospholipids)
RN  - 0 (silimat)
RN  - 7631-86-9 (Silicon Dioxide)
RN  - 9005-49-6 (Heparin)
SB  - IM
MH  - Adolescent
MH  - Adult
MH  - Aged
MH  - Aged, 80 and over
MH  - Animals
MH  - Drug Combinations
MH  - Drug Monitoring/*methods
MH  - Heparin/*therapeutic use
MH  - Humans
MH  - Indicators and Reagents
MH  - Linear Models
MH  - Middle Aged
MH  - *Partial Thromboplastin Time
MH  - Phospholipids/*therapeutic use
MH  - Rabbits
MH  - Silicon Dioxide/*therapeutic use
EDAT- 1998/07/31 00:00
MHDA- 1998/07/31 00:01
CRDT- 1998/07/31 00:00
PHST- 1998/07/31 00:00 [pubmed]
PHST- 1998/07/31 00:01 [medline]
PHST- 1998/07/31 00:00 [entrez]
AID - 98070104 [pii]
PST - ppublish
SO  - Thromb Haemost. 1998 Jul;80(1):104-8.