The page below is a sample from the LabCE course Bone Marrow Aspiration: Normal Hematopoiesis and Basic Interpretive Procedures. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Bone Marrow Aspiration: Normal Hematopoiesis and Basic Interpretive Procedures (online CE course) »
How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 97 CE courses, most popular
$95 Add to cart
Pick Your Courses
Up to 8 CE hours
$50 Add to cart
Individual course$20 Add to cart


In the metamyelocyte stage, the cytoplasm and nucleus continue to decrease in size. The cytoplasm achieves full secondary granule content. The chromatin becomes more dense, knotted, and compact, while the nucleus begins to indent and acquire the familiar "kidney bean" shape.
By the end of the stage, the cell will be similar in size to a mature neutrophil with similarly cytoplasmic granularity.

The top image to the right shows a fairly classic metamyelocyte. Observe the indented kidney bean-shaped nucleus and neutrophil-colored cytoplasm. Notice the clumped aggregates of chromatin in each pole of the nucleus. The vacuolated cytoplasm in this cell is an indication of toxic stress.

In the bottom image to the right, notice the metamyelocytes (see red arrows) and their chromatin patterns. The patterns becomes more dense and clumped as the metamyelocytes continue to mature to the band neutrophil stages (see blue arrows).