S-Monovette® ThromboExact
Specially designed for thrombocyte determination when pseudothrombocytopenia is suspected!

NEWS-Monovette® ThromboExact
For thrombocyte determination when pseudothrombocytopenia is suspected
The term pseudothrombocytopenia describes an erroneously low thrombocyte count. In contrast to a genuine
reduction of blood platelets, pseudothrombocytopenia does not constitute a clinical picture but, instead, a merepreanalytical phenomenon that happens to occur when working with automated blood cell analysers1, 2, 3.
Generally, pseudothrombocytopenia is caused by thrombocyte aggregation, which makes precise countingof the thrombocytes impossible. Aggregation most frequently occurs when EDTA is used as an anticoagulant.
However, patient-related aggregation can also occur with other additives used for anticoagulation, such asHeparin or Citrate.
Early detection of this phenomenon ensures that the diagnostic and therapeutic consequences of athrombocytopenia misdiagnosis are avoided.
The following graph shows an example of multiple-intolerance reactions:Citrate blood

EDTA blood

Blood from S-Monovette® ThromboExact

Thrombocytes (x 1,000/μl)

Heparin blood

Fig. 1:

Example of multiple-intolerance reactions (Rostock University Hospital)

According to special literature in this field, adding certain aminoglycoside antibiotics4,5 or using a CTAD solution6,7
may prevent in vitro aggregation of thrombocytes. Such inhibitors are, however, rarely used because they are
typically expensive and alter the blood/additive dilution ratio.
The S-Monovette® ThromboExact provides a solution to the problems described above. The product iscurrently being tested at the universities of Munich and Rostock for the determination of an accurate
thrombocyte count when EDTA- induced pseudothrombocytopenia and multiple-intolerance reactions occur.

Initial data compiled from these studies are illustrated as follows:

Thrombocytes (x 1,000/μl)

EDTA, immediately
EDTA, 4 hours
ThromboExact, immediately
ThromboExact, 4 hours

Patient No.

Fig. 2:

Thrombocyte values from EDTA blood and S-Monovettes ThromboExact analysed immediately and 4 hours after sampling
Munich University, Sysmex XE-2100)

Preparation

EDTA

CitrateThromboExact

Elapsed Time

2-4 h

2-4 himmediately

1h2hPatient No. 12126266265273258

Patient No. 13

57172279

279288284

261

Patient No. 1425313378398393384376

Patient No. 1537142

124

Patient No. 16

7772157149156

152

Patient No. 17

78213

222

281

281

150

Patient No. 18

1220142

Patient No. 19116356362

144

4h

5h7h

12 h
254

147

278267
142

Tab. 1: Thrombocyte count (in 1,000/μl) from blood treated with EDTA, Citrate, and S-Monovettes ThromboExact at defined times after
sampling (Rostock University, Sysmex XE 2100).

The preliminary results obtained from these studies to date are as follows:s The data compiled for the S-Monovette® ThromboExact confirm a case of genuine thrombocytopenia forpatient No. 3.
s The period of time after blood collection during which an EDTA-induced pseudothrombocytopenia manifests
varies among individual patients. This becomes apparent when comparing the thrombocyte count obtainedfor patients 1, 2, 6, and 7 with that for patients 8, 9, and 10.
s Patients 13, 16, and 18 show examples of multiple-intolerance reactions.
s The data obtained for patients 12, 13, 14, 16, and 18 reveal that the S-Monovette® ThromboExact provides
a correct thrombocyte count 12 hours after blood collection.

Conclusion:
Thrombocytes can still be correctly determined 12 hours after blood collection.
Intolerance reactions to EDTA and/or Citrate can be ascertained.
Corrections due to the dilution ratio are no longer necessary.
The specific nature of the S-Monovette® ThromboExact ensures assignment of the sample to the correct laboratory.

S-Monovette® ThromboExact
References
1: E. Gowland, H. E. M. Kay, J. C. Spillman und J. R. Williamson: Agglutination of platelets by a serum factor in
the presence of EDTA J. Clin. Path. 1969, 22, 460-464.
2: T. Nilsson und B. Norberg: Thrombocytopenia and pseodothrombocytopenia: A clinical and laboratory problem
Scand. J. Haematol. 1986, 37, 341-346.
3: F. Silvestri, L. Virgolini, C. Savignano, F. Zaja, M. Velisig und M. Baccarani: Incidence and Diagnosis of EDTADependent Pseudothrombocytopenia in a Consecutive Outpatient Population Referred for Isolated Thrombocytopenia Vox Sang 1995, 68, 35-39.
4: S. Sakurai, I. Shiojima, T. Tanigawa und K. Nakahara: Aminoglycosides prevent and dissociate the aggregationof platelets in patients with EDTA-dependent pseudothrombocytopenia Br. J. Haematol. 1997, 99, 817-823.
5: A. J. P. F. Lombarts, J. J. Zijlstra, R. H. M. Peters, C. G. Thomasson und P. F. H. Franck: Accurate Platelet
Counting in an Insidious Case of Pseudothrombocytopenia Clin Chem Lab Med 1999, 37, 1063-1066.
6: G. Contant, M. Goualt-Heilmann und J. L. Martinoli: Heparin inactivation during blood storage: its prevention byblood collection in citric acid, theophylline, adenosine, dipyridamole Thromb. Res. 1983, 31, 365-374.
7: O. Ohnuma, Y. Shirata und K. Miyazawa: Use of theophylline in the investigation of pseudothrombocytopenia

443a-200

This document may contain information on products that may not be available in particular countries

Technical modifications reserved

induced by edetic acid J. Clin. Pathol. 1988, 41, 915-917.

Ordering Information
Order No.

Description

Packaging

05.1168.001

S-Monovette® ThromboExact

50 pcs./inner box
500 pcs./case

SARSTEDT AG & Co.
P.O. Box 12 20
D-51582 Nümbrecht
Phone +49 2293 3050
Fax+49 2293 305- 122
info@sarstedt.com
www.sarstedt.com