The importance of manual white blood cell differential counts and platelet estimates in elephant hematology: blood film review is essential

Figures & data

Figure 1. Image composite of normal and reactive lymphocytes and monocytes, respectively, in elephants as commonly recognized by blood film evaluation. x100 objective. Wright-Giemsa stain.

Figure 2. Bland-Altman plots for comparison of white blood cell and platelet quantification methods as determined using an automated hematology analyzer and manual blood film evaluation in 50 elephants. The difference between automated and manual cell counts is plotted against the mean count of both methods for each cell type. Central lines depict the mean difference between the two methods, upper and lower lines represent limits of agreement, defined as the mean difference ±1.96 times the standard deviation of the differences.

Table 1. Comparison of means for hematological analytes of 50 elephants between automated (A) versus manual (M) white blood cell differential, and automated platelet count versus platelet estimate from the blood film.

Hematological analyte	Method	Mean	Standard deviation	Range	p value
Heterophils (K/µl)	A	0.29	0.23	0.00 − 0.93
	M	3.1	1.22	1.14 − 6.16	<0.0001
Lymphocytes (K/µl)	A	3.13	1.24	0.72 − 5.97
	M	2.11	1.14	0.22 − 5.29	<0.0001
Monocytes (K/µl)	A	3.14	1.20	1.17 − 5.84
	M	4.99	1.80	1.35 − 9.72	<0.0001
Eosinophils (K/µl)	A	2.94	1.27	1.18 − 6.33
	M	0.23	0.21	0.00 − 0.97	<0.0001
Basophils (K/µl)	A	0.06	0.07	0.00 − 0.37
	M	0.01	0.03	0.00 − 0.15	<0.0001
Platelets (K/µl)	A	294	91	106 − 509
	M	793	333	300 − 1650	<0.0001