Laboratory Assessment of von Willebrand Factor: Altered Interpretation of Laboratory Data,and Altered Diagnosis of von Willebrand's Disease

Abstract

Three laboratory assays for von Willebrand Factor (vWF), namely, (i) a standard "antigen" [antisera-enzyme-linked immunosorbent assay (ELISA)-based] (vWF :Ag), (ii) a standard ristocetin-dependent platelet agglutination procedure (vWF:RCof), and (iii) a newly developed ELISA-based functional vWF collagen binding assay (vWF:CBA), were coevaluated. We (a) assessed their ability to detect vWF under different assay conditions and (b) reevaluated normal vWF reference ranges using citrated plasma from >200 normal individuals. The following effective normal reference ranges were derived: vWF-Ag (40-200%), vWF:CBA (50-400%), and vWF:RCof (45-200%). Based on other laboratory data, caution is indicated in the interpretation of "borderline" or "equivocal" test results (e.g., 35-55%), since these may derive from normal individuals or from vWD patients. In addition, our study shows that selection of different assay conditions, different test plasma dilutions, or different test sample processing methods can also lead to differences in the "apparent" levels of detected vWF. For example, using plasma from 100 normal individuals processed as "test samples," we determined that higher sample dilutions tended to provide lower (dilution factor adjusted) assay results in the case of the vWF:Ag and vWF:CBA, and higher assay results in the case of the vWF.RCof, with greater differences noted in test samples containing higher levels of vWF. The explanation for these findings relate to the assay design. Thus, in the diagnostic laboratory, the standard vWF:Ag, vWF:CBA, and vWF:RCof assays procedures are designed to provide calibration curves that are "upward linear" in the (vWD) clinically important region of 0-50% of normal, with a plateau tending at higher vWF levels. Using these standard methodologies, and standard plasma dilutions, high-vWF level test samples will tend to fall on or near the plateau, and results will be unreliable, with a tendency to be exaggerated the higher the vWF. These findings have particular relevance to research studies measuring vWF in patients suffering various clinical conditions (e.g., thrombotic thrombocytopenic purpura, diabetes, renal failure) where higher than normal levels of vWF may be anticipated. In these cases, laboratory-derived vWF levels could be "misrepresented" if the study design did not take into account the need to revise the vWF testing procedure. Key Words: von Willebrand factor-von Willebrand's disease—Laboratory assessment-Normal ranges—Reference ranges—Diagnosis.

Get full access to this article

View all access options for this article.

References

Moroose R. , Hoyer LW von Willebrand factor and platelet function. Annu Rev Med 1986;37-157.

Giddings JC , Peake IR The investigation of factor VIII deficiency. In: Thompson JM , ed. Blood coagulation and haemostasis . New York: Churchill Livingstone , 1985:135.

Girma J-P. , Meyer D. , Verweij CL , et al. Structure-function relationship of human von Willebrand factor . Blood 1987;70: 605.

Sadler JE Review: von Willebrand factor. J Biol Chem 1991:266:22777.

Sadler JE , Gralnck HR Commentary: A new classification for von Willebrand disease. Blood 1994;84:676.

Sadler JE A revised classification on von Willebrand disease. Thromb Haemost 1994;71:520.

Mannucci PM , Altieri D. , Faioni E. Vasopressin analogues: their role in disorders of haemostasis. Ann NY Acad Sci 1987;509:71.

Rodeghiero F. , Castamann G. , Mannucci PM

Clinical indications for desmopressin (DDAVP) in congenital and acquired von Willebrand disease

Blood Rev 1991;5:155.

Mannucci PM , Cattaneo M. Desmopressin: a nontransfusional treatment of haemophilia and von Willebrand disease. Haemostasis 1992;22:276.

10.

Badimon L. , Badimon JJ , Chesebro JH , Fuster V. von Willebrand factor and cardiovascular disease. Thromb Haemost 1993;70:111.

11.

Jansson J-H. , Nilsson TK , Johnson O. von Willebrand factor in plasma: a novel risk factor for recurrent myocardial infarction and death . Br Heart J 199 1;66:351.

12.

Nichols TC , Bellinger DA , Reddick RL , et al. Role of von Willebrand factor in arterial thrombosis: studies in normal and von Willebrand disease pigs. Circulation 1991;83 (Suppl IV):IV-56.

13.

Bloom AL von Willebrand factor: clinical features of inherited and acquired disorders . Mayo Clin Proc 1991;66:743.

14.

Brinkhous KM , Reddick RL , Read MS , Nichols TC , Bellinger DA , Griggs TR von Willebrand factor and animal models: contributions to gene therapy, thrombotic thrombocytopenic purpura, and coronary artery thrombosis. Mayo Clin Proc 1991;66:733.

15.

Gralnick HR von Willebrand factor, integrins, and platelets: their role in cancer. J Lab Clin Med 1992; 119:444.

16.

Stehouwer Cda , Nauta Jjp , Zeldenrust GC , Hackeng Whl , Donker Ajm , den Ottolander Gjh. Urinary albumin excretion, cardiovascular disease, and endothelial dysfunction in non-insulin-dependent diabetes mellitus. Lancet 1992;340:319.

17.

Porta M. , La Selva M. , Molinatti PA von Willebrand factor and endothelial abnormalities in diabetic microangiopathy . Diabetes Care 1991;14:167.

18.

Kazatchkine M. , Sultan Y. , Caen JP , Bariety J. Bleeding in renal failure: a possible cause . BMJ 1976;Sept:612.

19.

Niesvizky R. , Calandri C. , Patel ND , Zhou S. , Potter BJ , Rand JH von Willebrand factor binding to collagen in patients with end-stage renal disease. J Lab Clin Med 1994;123:137.

20.

Ruggeri ZM , Ponticelli C. , Mannucci PM Factor VIII and chronic renal failure. BMJ 1977;Apr:1085.

21.

Herrmann RP , Marshall LR , Hurst PE Bleeding in renal failure: a possible cause . BMJ 1977;June:1601.

22.

Remuzzi G. , Livio M. , Roncaglioni MC , Mecca G. , Donati MB , de Gaetano G. Bleeding in renal failure: Is von Willebrand factor implicated? BMJ 1977;Aug:359.

23.

Wegmuller E. , Gruninger U. , Furlan M. , Beck EA , Hodler J. , Reubi FC Factor VIII activity in chronic renal disease . Nephron 1981;28:157.

24.

Castaman G. , Rodeghiero F. , Lattuada A. , La-Greca G. , Mannucci PM Multimeric pattern of plasma and platelet von Willebrand factor is normal in uremic patients . Am J Hematol 1993;44:266.

25.

Caron C. , Goudemand J. , Marey A. , Beague D. , Ducroux G. , Drouvin F. Are haemostatic and fibrinolytic parameters predictors of pre-eclampsia in pregnancy associated hypertension? Thromb Haemost 1991;66:410.

26.

Hansen J-B. , Wilsgard L. , Olsen JO , Osterud B. Formation and persistence of procoagulant and fibrinolytic activities in circulation after strenuous physical exercise. Thromb Haemost 1990;64:385.

27.

Jem C. , Eriksson E. , Tengbom L. , Risberg B. , Wadenvik H. , Jem S. Changes of plasma coagulation and fibrinolysis in response to mental stress . Thromb Haemost 1989;62:767.

28.

Brown JE , Bosak JO An ELISA test for the binding of von Willebrand antigen to collagen . Thromb Res 1986;43:303.

29.

Favaloro EJ , Grispo L. , Exner T. , Koutts J. Development of a simple collagen based ELISA assay aids in the diagnosis of, and permits sensitive discrimination between Type I and Type II, von Willebrand's disease . Blood Coag Fibrinolys 1991 ;2:285.

30.

Favaloro EJ Grispo L. , Dinale A. , Berndt M. , Koutts J. von Willebrand's disease: laboratory investigation using an improved functional assay for von Willebrand factor. Pathology 1993 ;25:152.

31.

Favaloro EJ , Dean M. , Grispo J. , Exner T. , Koutts J. von Willebrand's disease: use of collagen binding assay provides potential improvement to laboratory monitoring of desmopressin (DDAVP) therapy. Am J Hematol, 1994;45:205.

32.

Favaloro EJ , Facey D. , Grispo L. Laboratory assessment of von Willebrand factor: use of different assays can influence the diagnosis of von Willebrand's' disease, dependent on dif fering sensitivity to sample preparation and differential recognition of high molecular weight vWF forms . Am J Clin Pathol 1995;104:264.

33.

Healy Mjr , Ingram Gic. The "normal range" in tests of haemostasis. International Committee Communications . Thromb Haemost 1978;39:504.

34.

Sadler JE , Matsushita T. , Dong Z. , Tuley EA , Westfield LA Molecular mechanism and classification of von Willebrand disease. Thromb Haemost 1995;74:161.

35.

Blann AD , Mather H. , Miller JP , McCollum CN Atherosclerosis risk factors: variations in healthy hospital workers and members of local communities asymptomatic for vascular disease. Implications for normal controls. Br J Biomed Sci 1995;52:31.

36.

Ermens Aam , de Wild PJ , Vader HL , van der Graaf F. Four agglutination assays evaluated for measurement of von Willebrand factor (ristocetin cofactor activity). Clin Chem 1995;41:510.

37.

Blomback M. , Eneroth P. , Andersson O. , Anvret M. On laboratory problems in diagnosing mild von Willebrand's disease. Am J Hematol 1992 ;40:117.