Table 2.

Classic patterns of alterations in red blood cell components and related endpoints

	Erythrocytosis			Regenerative anemia			Iron deficiency	Nonregenerative anemia
	Relative	Primary	Secondary	Blood loss	IV hemolysis	EV hemolysis		ACD	Bone marrow suppression
RBC	↑	↑ to ↑↑↑	↑ to ↑↑↑	↓ to ↓↓↓	↓ to ↓↓↓	↓ to ↓↓	↓ to ↓↓↓	↓	↓ to ↓↓↓
Retica	-	↑ to ↑↑	↑ to ↑↑	- to ↑↑	- to ↑↑	- to ↑↑	- to ↓d	- to ↓	↓ to ↓↓↓
MCV	-	- to ↑	- to ↑	- to ↑	- to ↑	- to ↑	↓	-	-
MCHC	-	- to ↓	- to ↓	- to ↓	↓ to ↑b	- to ↓	- to ↓	-	-
Total bilirubin	-	-	-	-	- to ↑↑	↑ to ↑↑	-	-	-
Free Hgb	-	-	-	-	- to ↑↑c	-	-	-	-

Patterns described in this table indicate classic or expected changes in red blood cell components and associated endpoints due to these processes. However, duration of these processes, variations in the underlying causes of these conditions, and superimposition of multiple processes may result in differences between expected patterns of leukocyte changes and actual changes observed in an individual.

-, no apparent change; ↑, mild increase; ↑↑, moderate increase; ↑↑↑, marked increase; ↓, mild decrease; ↓↓, moderate decrease; ↓↓↓, marked decrease.

RBC, red blood cells; Retic, reticulocytes; MCV, mean corpuscular volume; MCHC, mean corpuscular hemoglobin concentration; Hgb, hemoglobin; IV, intravascular; EV, extravascular; ACD, anemia of chronic disease.

^aThe magnitude of reticulocyte count increases generally reflects the magnitude of red cell mass decreases; all decreases in red cell mass are initially preregenerative without apparent increases in reticulocyte counts.

^bWhen overwhelming intravascular hemolysis causes increases in plasma or serum free hemoglobin, MCHC may be artifactually increased, but MCHC is more commonly decreased due to increases in reticulocyte counts.

^cIncreases in plasma or serum free hemoglobin are only expected to occur with overwhelming intravascular hemolysis.

^dChronic iron deficiency anemia is typically nonregenerative with decreases in reticulocyte counts, but increases in reticulocyte counts may be observed following transfusion or iron supplementation.