Evaluation of reticulocyte hemoglobin content (RET‐He) in the diagnosis of iron‐deficient erythropoiesis in dogs

• Published in: Veterinary clinical pathology Vol. 46; no. 4; pp. 558 - 568
• Main Authors: Fuchs, Jannika, Moritz, Andreas, Grußendorf, Esther, Lechner, Jörg, Neuerer, Felix, Nickel, Rafael, Rieker, Thomas, Schwedes, Claudia, DeNicola, Dennis B., Russell, James, Bauer, Natali
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.12.2017
• Subjects: Bias; Canine; Coefficient of variation; Cut-off; Erythropoiesis; Hematology; Hemoglobin; Iron; Nutrient deficiency; prevalence; ProCyte Dx; reference interval; Veterinary medicine; prevalence; hematology; ProCyte Dx; reference interval; Canine
• ISSN: 0275-6382; 1939-165X
• DOI: 10.1111/vcp.12547

Background Reticulocyte hemoglobin content provided by the Siemens ADVIA (CHr) is an established marker of iron deficiency. The IDEXX ProCyte Dx hematology analyzer now provides a similar variable, reticulocyte hemoglobin equivalent (RET‐He). Objectives The objective was to evaluate RET‐He and its diagnostic utility in dogs, and to calculate a cutoff value for diagnosing iron‐deficient erythropoiesis (IDE). Furthermore, the prevalence of RET‐He values below this cutoff value was established. Methods One hundred and seventy‐one CBCs of healthy dogs were used to establish a RI. Stability of RET‐He was evaluated by repeated measurements over 48 hours (n = 10). The 25‐run coefficient of variation (CV) was calculated, and correlation and bias between measurements of RET‐He and CHr were assessed (n = 190). A cutoff value for diagnosing IDE was calculated. The utility of RET‐He in the detection of IDE was evaluated in 123 dogs. The prevalence of low RET‐He values was assessed retrospectively in a multicenter study (2012–2014) under participation of 7 veterinary clinics. Results Reticulocyte hemoglobin equivalent with an RI of 22.2 to 28.6 pg was statistically stable over 48 hours (P = .10). The CV was 1.8%. A fair correlation (ρ = 0.74) between RET‐He and CHr with a small bias of −0.6 pg was found. The cutoff value for diagnosing IDE was 20.9 pg (sensitivity: 85%; specificity: 99%). The prevalence of RET‐He values below 20.9 pg was 10.3% (1084/10,553 dogs). Conclusions RET‐He on the ProCyte Dx is a precise screening tool in dogs to detect iron‐deficient erythropoiesis.