Sultan Qaboos University Med J, May 2014, Vol. 14, Iss. 2, pp. e259-260, Epub. 7TH Apr 14 Submitted 23RD May 13 Revision Req. 25TH Aug 13; Revision Recd. 26TH Aug 13 Accepted 22ND Sep 13 1Department of Haematology, Sultan Qaboos University Hospital, Muscat, Oman; 2Ministry of Health, Muscat, Oman *Corresponding Author e-mail: arwa@squ.edu.om تعرض كريات الدم احلمراء للحرارة يؤدي لنتائج خمربية زائفة ومضللة اأروى الريامية، خليل الفار�صي، اإبراهيم ال�صحي، مرت�صى اخلابوري، حممد احلنيني، و هيدي ديفي�س Pseudopyropoikilocytosis Leading to Spurious Results *Arwa Z. Al-Riyami,1 Khalil Al-Farsi,1 Ibrahim Al-Shehhi,2 Murtadha Al-Khabori,1 Mohammed Al-Huneini,1 Heidi Davis1 INTERESTING MEDICAL IMAGE Figure 1: Blood film showing numerous small basophilic particles in clumps (arrow) and small chains (arrow head). Figure 2: Blood film showing striking red cell poikilocytosis with numerous microspherocytes (arrow head) and irregular pleomorphic fragments (red arrows). A necrotic neutrophil with distorted nuclei can also be seen in the field (black arrow). Pseudopyropoikilocytosis is an unusual phenomenon that is caused by the overheating of blood samples during transportation to the laboratory.1 This results in the red blood cells (RBCs) displaying similar morphological features to blood films of individuals with hereditary pyropoikilocytosis and severe thermal burns. The morphological findings in these two pathological conditions are related to the thermal instability of the RBCs.2 Both these morphological changes and the spurious results obtained from overheated samples can result in diagnostic confusion. A 21-year-old female was referred to the Department of Haematology at the Sultan Qaboos Hospital, Muscat, in July 2012 following abnormal laboratory results. Her vital signs were stable and the physical examination was unremarkable. A complete blood count (CBC) obtained by the CELL- DYN SAPPHIRE haematology analyser (Abbott Diagnostics, Lake Forest, Illinois, USA) showed marked thrombocytosis with a platelet count of 3,425 x 109/L (normal range: 150–450 x 109/L), leukocytosis with a white blood cell count of 16.8 x 109/L (normal range: 2.4–9.5 x 109/L), microcytosis with a mean corpuscular volume (MCV) of 68.5 fL (normal range: 78–95 fL), a high red cell distribution width (RDW) at 33.9% and an extremely high reticulocyte count of 5,435 x 109/L (normal range: 20–150 x 109/L). The blood film showed numerous small basophilic spherical particles in chains and variable clumps [Figures 1 and 2]. In addition, there was severe red cell poikilocytosis with bizarre poikilocytes, including microspherocytes and irregular pleomorphic fragments [Figure 2]. The white blood cells appeared necrotic. The potassium (K) level was high at 6.4 mmol/L (normal range: 3.5–5.1 mmol/L). Pseudopyropoikilocytosis Leading to Spurious Results e260 | SQU Medical Journal, May 2014, Volume 14, Issue 2 The patient underwent a repeat CBC, and the new sample revealed normal indices. The repeated blood film and K levels were normal. The initial abnormal results were therefore attributed to the large number of small red cell fragments and the numerous spherical particles, which were thought to be precipitated proteins. The initial collection tube expiry date was verified. Gram stains and cultures on the initial sample, as well as on new samples, were negative. Since the clinic was located at a distance from the laboratory, it was concluded that the previous abnormal results were due to the possible thermal exposure of the sample during transportation, resulting in in vitro haemolysis, altered morphology and spurious results. However, a manufacturing defect in the original collection tube could not be ruled out. Comment Spurious results on haematology analysers should be promptly identified to avoid potential misdiagnoses.3 Abnormal results require a careful evaluation of the scatter plots obtained by the analyser as well as an examination of a well-stained blood film. This case provides an example of the spurious results that can result after a thermal injury to a blood sample. In addition, it gives a clear illustration of the different morphological abnormalities seen in this setting. These results were obtained by a different instrument than those seen in the previously published literature, illustrating the importance of recognising the different characteristics of various analysers when examining the obtained results. The artificial thrombocytosis is likely to be secondary to the presence of the particles and the red blood cell fragments.4 Since the CELL-DYN SAPPHIRE haematology analyser uses impedance and optical methods (light scattering) of measurement, the presence of these particles caused an overestimation of the counts, as well as the low MCV and high RDW. Haematologists and haematology laboratory scientists must be aware of the characteristics of their analysers when evaluating CBC results, and be able to recognise and circumvent anomalous results. The lack of recognition of spurious results can lead to unnecessary investigations, undue anxiety and potentially harmful interventions. Any unusual or abnormal findings should prompt a request for a blood film and a repeat sample. References 1. Bain BJ, Liesner R. Pseudopyropoikilocytosis: A striking artifact. J Clin Pathol 1996; 49:772–3. doi:10.1136/jcp.49.9.772. 2. Zarkowsky HS, Mohandas N, Speaker CB, Shohet SB. A congenital haemolytic anaemia with thermal sensitivity of the erythrocyte membrane. Br J Haematol 1975; 29:537–43. doi: 10.1111/j.1365-2141.1975.tb02740.x. 3. Bain BJ, Lewis SM, Bates I. Basic haematological techniques. In: Lewis SM, Bain BJ, Bates I, Dacie J (Eds). Dacie and Lewis’s Practical Haematology, 9th edition. Philadelphia: Churchill Livingston, 2001. Pp.19–46. 4. Zandecki M, Genevieve F, Gerard J, Godon A. Spurious counts and spurious results on haematology analysers: A review. Part I: Platelets. Int J Lab Hematol 2007; 29:4–20.