Evaluation of the HemoCue ® WBC System as a Point of Care Diagnostic Tool for White Blood Cell Quantification in Pinnipeds

• Published in: Oceans
• Main Authors: Abby M. McClain, Emily R. Whitmer, Carlos Rios, Eric D. Jensen, Nicole I. Stacy, Shawn P. Johnson
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2022
• Subjects: Arctocephalus; Callorhinus; hematology; Mirounga; Phoca; point of care; Oceanography; GC1-1581; Phoca vitulina
• Online Access: https://doi.org/10.3390/oceans3010007; https://doaj.org/article/3020bf198bf146e1bd921073897e56b4

Point of care (POC) hematology testing can be valuable in triage and field settings. We assessed the accuracy between the HemoCue ® WBC system and two comparative analyzers, as well as the precision of the HemoCue ® WBC system in five different pinniped species: Zalophus californianus , Arctocephalus townsendi , Callorhinus urcinus , Phoca vitulina , and Mirounga angustirostris for white blood cell (WBC) quantification. In Zalophus ( n = 164; 106 from U.S. Navy Marine Mammal Program (Navy); 58 from The Marine Mammal Center (TMMC)), the HemoCue ® was compared to two hematology analyzers, Sysmex Xe-5000 and Vet ABC Plus. In Phoca ( n = 50; TMMC), Callorhinus ( n = 29; TMMC), Arctocephalus ( n = 17; TMMC), and Mirounga ( n = 67; TMMC), the HemoCue ® was compared to Vet ABC Plus only. Bland–Altman and Passing–Bablok agreement of HemoCue ® with Sysmex Xe-5000 and Vet ABC Plus analyzers were good for Zalophus , Arctocephalus , Phoca , and Mirounga but marginal with Callorhinus bias = 0.56 × 10 9 /L ( Zalophus Navy), −2.13 × 10 9 /L ( Zalophus TMMC), −1.59 × 10 9 /L ( Arctocephalus ), −2.48 × 10 9 /L 0.917 ( Phoca ), −0.01 × 10 9 /L ( Mirounga ), and −6.05 × 10 9 /L ( Callorhinus ). The coefficient of variation from triplicate runs of samples were within acceptable limits for all species (2.50% ± 1.63 ( Zalophus TMMC), 3.09% ± 2.14 ( Arctocephalus ), 2.47% ± 1.35 ( Callorhinus ), 2.88% ± 1.75 ( Phoca ), and 3.44% ± 2.53 ( Mirounga )), respectively. The presence of nucleated red blood cells (nRBC; 1–37 nRBC/100 WBC) did not significantly interfere with WBC counts in Zalophus , Callorhinus , and Phoca at the population level, but their presence should be evaluated at the individual level. The HemoCue ® provides an accurate method for WBC quantification with WBC counts up to 30 × 10 9 /L (upper limit of linearity of the analyzer) in Zalophus , Arctocephalus , Phoca , and Mirounga , but is less accurate in Callorhinus , and showed good precision in all species.