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Semin Thromb Hemost 2001; 27(3): 237-244
DOI: 10.1055/s-2001-15253
Copyright © 2001 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.: +1(212) 584-4662

Problems with Platelet Counting in Thrombocytopenia. A Rapid Manual Method to Measure Low Platelet Counts

Anton H. Sutor, Astrid Grohmann, Klaus Kaufmehl, Thomas Wündisch
  • Universitäts-Kinderklinik, Freiburg, Germany
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Publication History

Publication Date:
31 December 2001 (online)

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ABSTRACT

Because most automated platelet counters cannot be relied on in thrombocytopenia, clinicians face a problem when decision making is based on platelet counts. Therefore we evaluated a visual platelet counting method from a blood smear with white blood cells (WBCs) as reference (PCW = platelet count based on WBC). Platelet counting for 74 thrombocytopenic (<120 × 10 9 /L) children was performed with PCW and with an automated counter (impedance principle); both methods were compared with evaluation by phase-contrast microscopy as the standard method. The PCW correlated well with the phase-contrast microscopy evaluation (y = -0.38 + 1.01x, r 2 = 0.99). For platelet counts <20 × 109/L the maximal deviation was 2 × 109/L. The correlation between automated counts and the standard method was poor. The regression was y = 9.63 + 0.94x, r 2 = 0.86. For platelet counts <20 × 109/L the maximal deviation was 37 × 109/L; on average, 7 × 109/L platelets were counted in excess when compared with the standard method. PCW, in contrast to the automated impedance method, discriminated platelets from nonplatelet particles such as debris, fragments of red blood cells (hemolytic-uremic syndrome [HUS]) and of blast cells, and identified platelets of abnormal size. In addition, the appearance of platelets, WBCs, and RBCs gave clues to the etiology of thrombocytopenia, such as leukemia, infection, HUS, familial macrothrombocytopenia, and immune thrombocytopenia. PCW is a fast, reliable platelet counting method requiring less experience than the phase-contrast method. Visual evaluation from a stained smear clearly differentiates platelets and nonplatelet particles in contrast to most automated counters. In addition, the original smear can be preserved and reevaluated.

KEYWORD

Thrombocytopenia - platelet count - visual platelet counting - automated platelet counting

REFERENCES

  • 1 George J N, Woolf S H, Raskob G E. Idiopathic thrombocytopenic purpura: a practice guideline developed by explicit methods for the American Society of Hematology.  Blood . 1996;  88 3-40
    PubMedGoogle Scholar
  • 2 Sutor A H, Gaedicke G. Acute autoimmune thrombocytopenia.  Baillieres Clin Haematol . 1998;  11 381-389
    PubMedGoogle Scholar
  • 3 Kunz D. Possibilities and limitations of automated platelet counting procedures in the thrombocytopenic range.  Semin Thromb Hemost . 2001;  27 229-236
    Article in Thieme ConnectPubMedGoogle Scholar
  • 4 Sutor A H. Thrombozytenzählung bei Thrombozytopenie.  Pådiatr Prax . 1995;  50 43-52
    PubMedGoogle Scholar
  • 5 Pohland D. Evaluation of the automated haematology analyser Sysmex M-2000.  J Clin Chem Clin Biochem . 1989;  27 41-47
    PubMedGoogle Scholar
  • 6 Feissly R, Lüdin H. Microscopie par contrastes de phases.  Rev Hematol . 1948;  4 481
    PubMedGoogle Scholar
  • 7 O'Connor B H. A Color Atlas and Instruction Manual of Peripheral Blood Cell Morphology.  Baltimore: Williams & Wilkins; 1982
    Google Scholar
  • 8 Dickerhoff R, von Ruecker A. Enumeration of platelets by multiparameter flow cytometry using platelet-specific antibodies and fluorescent reference particles.  Clin Lab Haematol . 1995;  17 163-172
    PubMedGoogle Scholar
  • 9 Ault K A. Platelet counting: is there room for improvement?.  Lab Hematol . 1996;  2 139-143
    PubMedGoogle Scholar
  • 10 Komiyama Y, Teraoka A, Onishi K, Watanabe K, Takahashi H. Abnormal histograms of platelets and spuriously normalizing platelet counts by Sysmex cell counters in hemolytic uremic syndrome due to Escherichia coli O157:H7 infection [letter].  Thromb Haemost . 1997;  77 1220-1221
    PubMedGoogle Scholar
  • 11 Koh T, Kabutomori O, Nishiyama M. [Discrepancy of platelet numbers between automated blood cell analysis and manual counting in the patients with thrombocytopenia].  Rinsho Byori [in Japanese]. 1996;  44 889-894
    PubMedGoogle Scholar
  • 12 Sutor A H, Harms A, Kaufmehl K. Acute ITP in childhood. Retrospective and prospective survey in Germany.  Semin Thromb Hemost . 2001;  27 253-268
    Article in Thieme ConnectPubMedGoogle Scholar
  • 13 Fonio A. Über ein neues Verfahren der Blutplättchenzählung.  Chirurgie . 1912;  117 176-185
    PubMedGoogle Scholar
  • 14 Sutor A H. Das Blutbild und seine Altersabhängigkeit.  Kinderkrankenschwester . 1993;  12 98-100
    PubMedGoogle Scholar
  • 15 Rosenkranz B, Wisser H, Bode C. Pseudothrombozytopenie-eine Störung der Thrombozytenzahlbestimmung.  Dtsch Med Wochenschr . 1985;  110 492-495
    PubMedGoogle Scholar
  • 16 Greinacher A, Mueller-Eckhardt C. Hereditary types of thrombocytopenia, an important differential diagnosis in chronic thrombocytopenia. In: Sutor AH, Thomas KB, eds. Thrombocytopenia in Childhood Stuttgart: Schattauer 1994: 191-198
    Google Scholar
  • 17 Sutor A H. Abklärung einer Blutungsneigung.  Hämostaseologie . 2000;  20 1-7
    PubMedGoogle Scholar
  • 18 Warkentin T E, Hayward C P, Boshkov L K. Sera from patients with heparin-induced thrombocytopenia generate platelet-derived microparticles with procoagulant activity: an explanation for the thrombotic complications of heparin-induced thrombocytopenia.  Blood . 1994;  84 3691-3699
    CrossrefPubMedGoogle Scholar
  • 19 Gildein H P, Onaldi D, Gordjani N. Acute renal failure due to mechanical haemolysis after percutaneous catheter occlusion of a patent arterial duct [letter].  Int J Cardiol . 1998;  63 317-318
    CrossrefPubMedGoogle Scholar
      >