Pseudothrombocytopenia occurs in up to 0.1% of all CBCs and is usually caused by EDTA-dependent platelet agglutinating antibody.
1,2 Other mechanisms include artifacts of blood collection, monoclonal platelet agglutinin, platelet reactive cold agglutination and platelet satellitism where platelets form
Edta dependent rosetting around neutrophils and monocytes.
3 Use of an alternate anticoagulant such as citrate or
Heparin may be helpful. However, up to 17% of patients with
Edta dependent pseudothrombocytopenia also show this phenomenon with citrate.
4 This condition is clinically benign and is not associated with any pathological significance.
5 Accurate diagnosis of pseudothrombocytopenia is necessary as unrecognized spurious thrombocytopenia causes significant health expenditure and discomfort to the patients. Unnecessary clinical concern leads to inappropriate therapy such as blood transfusions and withholding of surgical procedures.
4 Measurement of platelet counts by modern automated analyzers is more accurate and economical, however, platelet clump "flag" on the CBC must prompt a thorough peripheral blood smear examination.
5
This case underlines the importance of routine peripheral blood smear examination and appropriate interpretation of platelet histogram.
Acknowledgment
We thank Dr. Chandrakala S (HOD clinical hematology) and Dr. Farah Jijina for their valuable inputs.
| References : |
- Payne BA, Pierre RV. Pseudothrombocytopenia: a laboratory artifact with potentially serious consequences. Mayo Clin Proc. 1984;59:123-125.
- Berkman N, Michaeli Y, Or R, Eldor A. EDTA-dependent pseudothrombocytopenia: a clinical study of 18 patients and a review of the literature. Am J Hematol. 1991;36:195-201.
- Qureshi, B. EDTA-Dependent pseudothrombocytopenia. LabMed. 1998;29: 471-473.
- Nagler M, Keller P, Siegrist D, Alberio L. A case of EDTA-dependent pseudothrombocytopenia: simple recognition of an underdiagnosed and misleading phenomenon. BMC Clin Pathol. 2014;14:19
- Tan G, Stalling M, Dennis G, Nunez M, Kahwash SB. Pseudothrombocytopenia due to Platelet Clumping: A Case Report and Brief Review of the Literature. Case Rep Hematol. 2016;2016:3036476.
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