Thromb Haemost 1999; 81(01): 66-70
DOI: 10.1055/s-0037-1614420
Review Article
Schattauer GmbH

Influence of Three Types of Automated Coagulometers on the International Sensitivity Index (ISI) of Rabbit, Human, and Recombinant Human Tissue Factor Preparations

A Multicenter Study
A. M. H. P. van den Besselaar
1   From the Haemostasis and Thrombosis Research Center, Leiden University Medical Center, Leiden, The Netherlands
,
L. L. Houbouyan
2   Hôpital Ambroise Paré, Service Central d'immuno-hématologie, Boulogne, France
,
M. F. Aillaud
3   Hôpital de la Timone, Laboratoire d'hématologie, Marseille, France
,
K. W. E. Denson
4   Thame Thrombosis and Haemostasis Research Foundation, Thame, Oxon, UK
,
M. Johnston
5   Hamilton Civic Hospitals Research Centre, Hamilton, Ontario, Canada
,
S. Kitchen
6   Royal Hallamshore Hospital, Department of Haematology, Sheffield, UK
,
T. L. Lindahl
7   University Hospital, Department of Clinical Chemistry, Linköping, Sweden
,
M. Marren
8   Beaumont Hospital, Coagulation Laboratory, Department of Haematology, Dublin, Ireland
,
M. E. Martinuzzo
9   University Institute of Biomedical Sciences, Favaloro Foundation, Buenos Aires, Argentina
,
C. Droullé
10   Hôpital Robert Debré, Laboratoire Central d'hématologie, Reims, France
,
A. Tripodi
11   A. Bianchi Bonomi Hemophilia and Thrombosis Centre, IRCCS Maggiore Hospital, Milano, Italy
,
C. Vergnes
12   Hôpital Cardiologique Haut Lévêque, Laboratoire d'hémobiologie, Pessac, France
› Author Affiliations
Further Information

Correspondence to:

Dr. A. M. H. P. van den Besselaar
Haemostasis and Thrombosis
Research Centre, Building 1
C2-R, Leiden University Medical Centre
P.O. Box 9600, 2300 RC Leiden
The Netherlands
Phone: +31 71 526 1894   
Fax: +31 71 526 6755

Publication History

Received27 February 1998

Accepted after resubmission23 September 1998

Publication Date:
08 December 2017 (online)

 

Summary

Five tissue factor reagents and three types of automated instruments for prothrombin time (PT) determination were studied in an international multicenter collaborative exercise. The purpose of this work was to determine the international sensitivity index (ISI) for each combination of reagent and instrument against the international reference preparation RBT/90. Each type of instrument was used by 3 or 4 centers to assess the interlaboratory variation of the ISI. The interlaboratory variation of the ISI for each combination of reagent and instrument ranged between 0.4% and 7.8% coefficient of variation. For three reagents, the mean ISI values for ACL (nephelometric) and STA (mechanical) were practically identical, but the mean ISI values for MLA (photo-optical) were at least 10% higher. For two other reagents prepared from rabbit tissue, the mean ISI values increased in the order ACL, STA, MLA. The widest range of mean ISI values was noted with one rabbit tissue factor reagent: 1.68 for ACL and 2.00 for MLA. Exclusion of patient specimens with INR <1.5 and INR >4.5 determined by the international reference preparation resulted in a slight decrease of the mean ISI.

The interlaboratory variation of the International Normalized Ratio (INR) was assessed from the results obtained with common lyophilized and deep-frozen plasmas. The use of instrument-specific ISI values resulted in reduced interlaboratory variation of the INR. It is recommended that thromboplastin manufacturers provide instrument-specific ISI values.


 



Correspondence to:

Dr. A. M. H. P. van den Besselaar
Haemostasis and Thrombosis
Research Centre, Building 1
C2-R, Leiden University Medical Centre
P.O. Box 9600, 2300 RC Leiden
The Netherlands
Phone: +31 71 526 1894   
Fax: +31 71 526 6755