Reference intervals for reticulocyte indices, immature reticulocyte fraction, and the percentage of hypochromic red blood cells in adult large breed dogs using the ADVIA 2120 hematology analyzer

Abstract

Reticulocyte indices are used to characterize anemia, including the identification of regeneration. In people, the immature reticulocyte fraction (IRF), percentage of hypochromic red blood cells (%HYPO‐RBC), and other reticulocyte indices have been used as earlier indicators of erythropoiesis and as valuable monitoring tools in the assessment of various therapies. The reference intervals (RI) of the IRF and %HYPO‐RBC have not been reported in dogs. The objective of this study was to establish RIs for novel variables (IRF, %HYPO‐RBC, and CH‐delta) and assess RIs for more commonly reported reticulocyte indices in healthy dogs. RIs were calculated from blood results retrospectively collected from 106 client‐owned healthy dogs at the time of induction into a blood donor program using the ADVIA 2120 hematology analyzer (Siemens Healthcare Diagnostics). For the calculation of RIs, appropriate tests were applied for outlier detection and normality assessment. For variables normally distributed, RIs and their respective 90% confidence intervals (CIs) were calculated using parametric methods, while for variables not normally distributed, robust methods were used and bootstrapping for calculating the 90% CIs. The following RIs were established: reticulocyte hemoglobin content (CHr) 24.5‐28 pg, mean reticulocyte volume (MCVr) 85.9‐99.3 fL, mean corpuscular hemoglobin concentration of reticulocytes (CHCMr) 271.0‐306.3 g/L, IRF 10.4%‐43.5%, CH‐delta 0.5‐4.3 pg, and percentage of hypochromic red blood cells (%HYPO‐RBC) 0.10%‐0.80%. The results of this study provide RIs for novel reticulocyte variables. Further studies are required to determine the clinical utility of IRF, %HYPO‐RBC, and CH delta as early indicators of erythropoietic activity in canine patients.

The Immature Reticulocyte Fraction (IRF) in the Sysmex XN-1000V Analyzer Can Differentiate between Causes of Regenerative and Non-Regenerative Anemia in Dogs and Cats

“…While the IRF is also used in human medicine to differentiate between causes of NRA (detect latent iron deficiency in blood donors, predict the appearance of bone marrow aplasia, etc.) [6,20], no publications in veterinary medicine are available in this regard. Here, we demonstrate that dogs and cats with BMF show a lower IRF compared to dogs with OTH.…”

“…In human medicine, the IRF is not only used for diagnosis, but also in the treatment monitoring of several types of anemia [20]. For example, the IRF can guide mineral replacement (cobalamin, folates, and iron) in the treatment of nutritional anemias [7] or the use of erythropoiesis-stimulating agents in anemia due to renal failure, AIDS, or myelodysplastic syndromes [5].…”