Fragmented red blood cells (FRC)
What is FRC?
FRC is a research parameter derived from a complete blood count (CBC) with reticulocyte measurement of an EDTA blood sample. It enumerates fragmented red blood cells (also known as schistocytes) formed as a consequence of mechanical damage, usually in the context of turbulent blood flow or contact with a pathologically altered endothelium.
We suggest automated FRC% as a rapid and highly sensitive index for screening of paediatric HUS [haemolytic uraemic syndrome].
Benefits
The clinical benefit of measuring FRC lies in assessing or excluding fragmented red blood cells in suspected cases across a wide range of disorders, from thrombotic microangiopathy and essential thrombocytosis to thalassaemias and haemolytic uraemic syndrome [1–4].
A laboratory can benefit from measuring FRC by providing a fast and highly sensitive screening for schistocytes, thus reducing the smear workload [1].
Reference ranges [5]
FRC# (fragmented red blood cell count): 0.0000 – 0.0029 × 1012/L
FRC% (fragmented red blood cell percentage): 0.00 – 0.06%
How is FRC measured?
FRC is a research parameter obtained from all Sysmex analysers equipped with the reticulocyte (RET) channel.
Fragmented red blood cells have a smaller size than intact red blood cells; thus, they are enumerated from a dedicated area of the RET scattergram below the red blood cell population, while showing minimal fluorescence due to the absence of organelles.
References
[1] Hisasue M et al. (2021): Modification of the Algorithm Used by Automated Hematology Analyzer XN-3000 Improves Specificity in the Detection of Schistocytes. Clin Lab 67(1).
[2] Hantaweepant C et al. (2020): Comparison between optical microscopy and the Sysmex XN-3000 for schistocyte determination in patients suspected of having schistocytosis. Health Sci Rep 3(1): e138.
[3] Govindarajan S et al. (2021): Usefulness of automated fragmented red blood cell percentage in the diagnosis of paediatric haemolytic uraemic syndrome. Int J Lab Hematol 43(1): 40–43.
[4] Lesesve JF et al. (2012): Fragmented red blood cells automated measurement is a useful parameter to exclude schistocytes on the blood film. Int J Lab Hematol 34(6): 566–576.
[5] L van Pelt J et al. (2022): Reference intervals for Sysmex XN hematological parameters as assessed in the Dutch Lifelines cohort. Clin Chem Lab Med 60(6): 907–920.
