Name of the Procedure:

Blood count; manual differential WBC count, buffy coat

Summary

A manual differential white blood cell count is a laboratory test that involves examining a blood sample under a microscope to identify and count the different kinds of white blood cells (WBCs). The buffy coat refers to the thin layer of concentrated cells that forms when a blood sample is spun in a centrifuge, which includes WBCs and platelets.

Purpose

The test is used to diagnose and monitor conditions that affect the immune and hematologic systems, such as infections, inflammation, bone marrow disorders, and leukemias. The goal is to provide detailed information about the types and proportions of WBCs in the blood.

Indications

• Suspected infection or inflammation
• Symptoms indicative of blood disorders, such as unexplained fever, fatigue, bruising, or bleeding
• Monitoring for patients undergoing chemotherapy or radiation therapy
• Unexplained abnormal results in an automated blood count

Preparation

• No specific preparation needed, though following general blood draw guidelines is advisable.
• Patients should inform their doctors about any medications they are taking as some drugs can affect blood cell counts.

Procedure Description

1. A blood sample is drawn from a vein, usually in the arm.
2. The sample is placed in a centrifuge to separate the blood components, forming the buffy coat.
3. A technician prepares a slide with a smear of the buffy coat and stains it for better visualization of the cells.
4. The slide is examined under a microscope.
5. The technician counts and identifies the different types of WBCs (e.g., neutrophils, lymphocytes, monocytes, eosinophils, basophils).

Duration

The entire process, from blood draw to counting the WBCs, usually takes a few hours, though the actual microscopic examination and counting may take about 30 minutes.

Setting

Typically performed in a clinical laboratory within a hospital or outpatient clinic.

Personnel

• Phlebotomist or nurse to draw the blood sample.
• Clinical laboratory technician or hematologist to prepare the slide and perform the differential count.

Risks and Complications

• Possible bruising or infection at the blood draw site (rare).
• Misidentification of cell types can occur, though very rare with trained personnel.

Benefits

• Accurate identification and quantification of WBC types.
• Helps diagnose infections, blood disorders, and monitor ongoing treatments.
• Immediate feedback, usually within a day.

Recovery

• No significant recovery steps are needed.
• Patients can resume normal activities immediately after the blood draw.

Alternatives

• Automated differential WBC count: Faster but less detailed, especially in cases with abnormal cells.
• Flow cytometry: More detailed analysis but more expensive and less widely available.
• Other specialized blood tests: Depending on the condition being investigated.

Patient Experience

• Mild discomfort during the blood draw, similar to a standard blood test.
• Typically no pain or discomfort during the counting process itself.
• Pain management is generally unnecessary, though some patients may feel anxious during blood draws and may benefit from supportive measures such as relaxation techniques or topical anesthetics.