Thromb Haemost 1991; 65(03): 263-267
DOI: 10.1055/s-0038-1648132
Original Article
Schattauer GmbH Stuttgart

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

A M H P van den Besselaar
The Thrombosis and Haemostasis Research Unit, Department of Haematology, Leiden University Hospital, Leiden, The Netherlands
,
R M Bertina
The Thrombosis and Haemostasis Research Unit, Department of Haematology, Leiden University Hospital, Leiden, The Netherlands
› Author Affiliations
Further Information

Publication History

Received: 31 July 1990

Accepted after revision 05 November 1990

Publication Date:
02 July 2018 (online)

Summary

In a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.

The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.

Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

 
  • REFERENCES

  • 1 WHO Expert Committee on Biological Standardization. Twenty-eighth Report. WHO Tech Rep Ser 1977 610. 14
  • 2 Loeliger EA, Van den Besselaar AMHP, Hermans J, Van der Velde EA. Certification of three reference materials for thromboplastins. BCR Information. Commission of the European Communities, Brussels 1981
  • 3 Hermans J, Van den Besselaar AMHP, Loeliger EA, Van der Velde EA. A collaborative calibration study of reference materials for thromboplastins. Thromb Haemostas 1983; 50: 712-717
  • 4 WHO Expert Committee on Biological Standardization. Thirty-third Report. WHO Tech Rep Ser 1983 687. 81-105
  • 5 Van den Besselaar AMHP. The certification of the second reference material for rabbit thromboplastin. . BCR Information, EUR 11686. Commission of the European Communities, Brussels 1988
  • 6 Thomson JM, Tomenson JA, Poller L. The calibration of the second primary international reference preparation for thromboplastin (thromboplastin, human, plain, coded BCT/253). Thromb Haemostas 1984; 52: 336-342
  • 7 Thomson JM, Darby KV, Poller L. Calibration of BCT/441, the ICSH reference preparation for thromboplastin. Thromb Haemostas 1986; 55: 379-382
  • 8 Van den Besselaar AMHP, Hermans J, Beeser H, Loeliger EA. Long-term stability of international reference preparations for thromboplastins. Br J Haematol 1988; 68: 321-328
  • 9 Poller L, Hirsh J. A simple system for the derivation of International Normalized Ratios for the reporting of prothrombin time results with North American Thromboplastin Reagents. Am J Clin Pathol 1989; 92: 124-126
  • 10 Kirkwood TBL. Calibration of reference thromboplastins and standardisation of the prothrombin time ratio. Thromb Haemostas 1983; 49: 238-244