Properties of Optical Data from Activated Partial Thromboplastin Time and Prothrombin Time Assays

Summary

Changes in characteristics of optical transmittance data from coagulation assays were examined as a function of concentration of coagulation proteins or anticoagulants. Transmittance data were collected for activated partial thromboplastin time (APTT) and prothrombin time (PT) assays from: 1) plasmas prepared by mixing normal plasmas with deficient plasmas to give varying levels of coagulation proteins; 2) plasmas containing added heparin; and 3) 200 specimen plasmas that were also assayed for fibrinogen, coagulation factors, and other components. Optical profiles were characterized using a set of parameters describing onset and completion of coagulation, magnitude of signal change, rate of coagulation and other properties. Results indicated that parameters other than those typically reported for APTT and PT are associated with individual deficiencies, but that diagnosis of specimen status on the basis of optical data is complex. These results suggest possibilities for expanded interpretation of PT/APTT optical data for clinical or research applications.

• References

• 1 White IIGC, Marder VJ, Colman RW, Hirsh J, Salzman EW. Approach to the Bleeding Patient. In: Hemostasis and Thrombosis: Basic Principles and Clinical Practice. Colman RW, Hirsh J, Marder VJ, Salzman EW. eds. J. B. Lippincott Company; Philadelphia, PA: 1994. pp 1134-1147
• 2 Rossi E, Mondonico P, Lombardi A, Preda L. Method for the determination of functional (clottable) fibrinogen by the new family of ACL coagulometers. Thromb Res 1988; 52: 453-468
• 3 Baumann P, Juergensen T, Heuck C-C. Computerized analysis of thein vitro activation of the plasmatic clotting system. Haemostasis 1989; 19: 309-321
• 4 Heuck C-C, Baumann P. Kinetic analysis of the clotting system in the presence of heparin and depolymerized heparin. Haemostasis 1991; 21: 10-18
• 5 Givens TB, Braun P, Fischer TJ. Predicting the presence of plasma heparin using neural networks to analyze coagulation screening assay optical profiles. Comput Biol Med 1996; 26: 463-476
• 6 Cross SS, Harrison RF, Kennedy RL. Introduction to neural networks. Lancet 1995; 346: 1075-1079
• 7 Baxt WG. Application of artificial neural networks to clinical medicine. Lancet 1995; 346: 1135-1138
• 8 Dybowski R, Gant V. Artificial neural networks in pathology and medical laboratories. Lancet 1995; 346: 1203-1207
• 9 Givens T, Fischer TJ, Swan R, Davis R. MDA 180 methods for the determination of fibrinogen concentration. Organon Teknika Technical Bulletin, Durham, NC 1995; pp 01-11
• 10 Downey C, Kazmi R, Toh CH. The impact of transmittance waveforms from an automated coagulation analyzer on the early identification of disseminated intravascular coagulation. Blood Coag Fibrinol 1996; 07: 723
• 11 SAS Procedures Guide. SAS Institute Inc., Cary, NC 1990: 209-236
• 12 Bain B, Forster T, Sleigh B. Heparin and the activated partial thromboplastin time – a difference between thein-vitro andin-vivo effects and implications for the therapeutic range. Am J Clin Pathol 1980; 74: 668-673
• 13 D’ Angelo A, Seveso MP, D’Angelo SV, Gilardoni F, Dettori AG, Bonini P. Effect of clot-detection methods and reagents on the activated partial thromboplastin time (APTT). Am J Clin Pathol 1990; 94: 297-306
• 14 Reed SV, Haddon ME, Denson KWE. An attempt to standardize the APTT for heparin monitoring, using the P. T. ISI/INR system of calibration. Results of a 13 centre study. Thromb Res 1994; 74: 515-522
• 15 Massignon P, Moulsma M, Bondon P, Debize G, Abidi H, Buttin T, Bon C, Pillonchery G, Coeur P. Prothrombin time sensitivity and specificity to mild clotting factor deficiencies of the extrinsic pathway: evaluation of eight commercial thromboplastins. Thromb Haemost 1996; 75: 590-594
• 16 Van den Besselaar AMHP, Meeuwisse-Braun J, Jansen-Grueter R, Bertina RM. Monitoring heparin by the activated partial thromboplastin time – the effect of pre-analytical conditions. Thromb Haemost 1987; 57: 226-231
• 17 Naghibi F, Han Y, Dodds WJ, Lawrence CE. Effects of reagent and instrument on prothrombin times, activated partial thromboplastin times and patient/control ratios. Thromb Haemost 1988; 59: 455-463
• 18 Thomson JM, Tabemer DA, Poller L. Automation and prothrombin time: a United Kingdom study of two widely used coagulometers. J Clin Pathol 1990; 43: 679-684
• 19 Pi DW, Raboud JM, Filby C, Carter CJ. Effect of thromboplastin and coagulometer interaction on the precision of the International Normalized Ratio. J Clin Pathol 1995; 48: 13-17
• 20 Shojania AM, Tetreault J, Turnbull G. The variations between heparin sensitivity of different lots of activated partial thromboplastin time reagent produced by the same manufacturer. Am J Clin Pathol 1988; 89: 19-23