Comparison between a Camera and a Four Quadrant Detector, in the Measurement of Red Blood Cell Deformability as a Function of Osmolality
Arie Finkelstein 1, Hugues Talbot 1, Suat Topsu 2, Thérèse Cynober 3,
Loïc Garçon
4, Gregor Havkin
5,
and
Frans Kuypers 6
1. Université Paris-Est, ESIEE Paris, ISYS, Noisy-le-Grand, France
2. Université de Versailles Saint Quentin en Yvelines, LISV, Versailles, France
3. Hôpital de Bicêtre, Laboratoire d'Hématologie, Le Kremlin-Bicêtre, France
4. Hôpital Saint-Antoine, Laboratoire d'Hématologie, Paris, France
5. Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
6. Children's Hospital Oakland Research Institute, Oakland, CA, USA
2. Université de Versailles Saint Quentin en Yvelines, LISV, Versailles, France
3. Hôpital de Bicêtre, Laboratoire d'Hématologie, Le Kremlin-Bicêtre, France
4. Hôpital Saint-Antoine, Laboratoire d'Hématologie, Paris, France
5. Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
6. Children's Hospital Oakland Research Institute, Oakland, CA, USA
Abstract— The ability of red blood cells (RBC) to deform under vascular conditions is essential for circulation. RBC deformability, measured at different shear rates and osmolalities, provides a useful way to evaluate RBC function and is used to diagnose several hereditary blood disorders. In clinical practice, ektacytometry has been used as a routine automated technique for measuring RBC deformability under shear stress at known osmolalities. RBC suspension is exposed to laser light and the resulting diffraction pattern is recorded. The mean deformability of the cells is characterized by the diffraction pattern. Our study is the first to compare the correspondence between two methods that measure diffraction simultaneously, on the same apparatus. Additionally, while others conducted studies under varying shear we used varying osmolalities. A laser beam splitter produced two identical diffraction patterns, evaluated by synchronous data acquisition and analysis: One pattern was acquired by a digital camera and analyzed by image processing software. The other was analyzed using photodiode measurement at four fixed points and a microcontroller interface. Data analysis resulted in two deformability vs. osmolality curves. Comparing these curves shows excellent overlap in shape with a clear difference in amplitude. Since routine patient curves are always compared to a normal control curve, the amplitue difference is not significant. Our results indicate that either method may be used for clinically-usable interpretation of RBC deformability, but also that additional studies are required in order to compare repeatability for both methods, and to demonstrate that the two curves overlap for a variety of pathologies.
Index Terms — Ektacytometer, ektacytometry, deformability, red blood cell, osmolality, diffraction, shear stress
Cite: Arie Finkelstein, Hugues Talbot, Suat Topsu, Thérèse Cynober, Loïc Garçon, Gregor Havkin, and Frans Kuypers, "Comparison between a Camera and a Four Quadrant Detector, in the Measurement of Red Blood Cell Deformability", Journal of Medical and Bioengineering vol. 2, no. 1, pp.62-65, 2013. doi: 10.12720/jomb.2.1.62-65
Index Terms — Ektacytometer, ektacytometry, deformability, red blood cell, osmolality, diffraction, shear stress
Cite: Arie Finkelstein, Hugues Talbot, Suat Topsu, Thérèse Cynober, Loïc Garçon, Gregor Havkin, and Frans Kuypers, "Comparison between a Camera and a Four Quadrant Detector, in the Measurement of Red Blood Cell Deformability", Journal of Medical and Bioengineering vol. 2, no. 1, pp.62-65, 2013. doi: 10.12720/jomb.2.1.62-65
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