Procedures, Assays, and Normal Values	23

Lymph Node Biopsy and Tumor Biopsy

These procedures, less invasive than bone marrow biopsy, are a simple and often diagnostically sufficient method for lymph node enlargement or other intumescences. The unanesthetized, disinfected skin is sterilized and pulled taut over the node. A no. 1 needle on a syringe with good suction is pushed through the skin into the lymph node tissue (Fig. 7). Tissue is aspirated from several locations, changing the angle of the needle slightly after each collection, and suction maintained while the needle is withdrawn into the subcutis. Aspiration ceases and the syringe is removed without suction. The biopsy harvest, which is in the needle, is extruded onto a microscopy slide and smeared out without force or pressure using a cover glass (spreader slide). Staining is done as described previously for blood smears.

24 Physiology and Pathophysiology of Blood Cells

1.

Skin puncture

2.

Aspiration

3.

Collecting aspirates from different lymph node locations

4.

Detaching the syringe body, equalizing the pressure difference

5.

Removal of the syringe body and cannula

6.

Pulling back the syringe barrel

7.

Pushing the biopsy material onto a slide

Fig. 7 Procedure for lymph node biopsy