Table 1. Reference Guide for Grading Red Blood Cell Morphology (RBC-M) /hpf (100 × oil) [19].

RBCs description	Normal	Occasional/rare	Mild/slight +1	Moderate +2	Marked +3
Microcyte	MCV 80 - 99 fL		MCV 70 - 79 fL (25% smaller than nucleus of small lymphocyte)	MCV 60 - 69 fL (26-49% smaller than nucleus of small lymphocyte)	MCV < 60 fL (≥ 50% smaller than nucleus of small lymphocyte)
Macrocyte			MCV 100 - 110 fL (25% larger than nucleus of small lymphocyte)	MCV 111 - 125 fL (26-49% larger than nucleus of small lymphocyte)	MCV > 125 fL (≥ 50% larger than nucleus of small lymphocyte)
Hypochromasia	MCH 27 - 34 pg	< 5% but present	5-15% (MCH 2 - 26 pg)	16-40% (MCH 18 - 21 pg)	> 40% (MCH < 18 pg)
Polychromasia		< 3% but present	3-5%	6-20%	> 20%
Target cells		< 5% but present	5-10%	11-25%	> 25%
Oval macrocytes		< 5% but present	6-20%	21-50%	> 50%
Anisocytosis		< 15%	15-25%	26-49%	50-89%
Poikilocytosis		< 1%	1-5%	6-10%	> 10%

MCV: mean corpuscular volume; MCH: mean corpuscular hemoglobin, fL: femtoliter; pg: pictogram.