Peripheral Smear Examination

Peripheral Smear Examination test evaluates the different components of the blood. The smear evaluates the red blood cells, white blood cells, and platelets as well as other abnormalities such as the presence of parasites. The blood smear test is ordered to diagnose the cause of unexplained jaundice, unexplained anemia, unknown fever, and severe infection.

The number and the appearance of blood cells can be affected by a variety of diseases such as the smaller size of RBCs may indicate a type of anemia whereas increased number of WBCs may indicate infection.

A blood smear test is said to be normal when the sample contains an optimum number, size and shape of blood cells. The results are considered abnormal when cells have an abnormality in shape, size, and number.

The peripheral smear examination evaluates the red blood cells (RBCs), white blood cells (WBCs), platelets and determines their relative percentages in the blood. It also helps in detecting, diagnosing, and monitoring deficiencies. Along with that, it detects diseases and disorders which involves the production of blood cells, their function, and lifespan.

To make a peripheral smear, a drop of blood is taken from the patient’s blood sample and is spread in a thin layer onto a glass slide. The slide is then stained with special stains. After the staining, the slide is examined and evaluated under the microscope for blood cells.

The following cells can be evaluated in the slide:

• White blood cells (WBCs or leukocytes) – Their function is to fight infections and participate in immune responses.

• Red blood cells (RBCs, erythrocytes) – Their function is to carry oxygen to the tissues.

• Platelets (Thrombocytes) – These are small cell fragments which play an important role in blood clotting.

Platelets are produced and mainly mature in the bone marrow just like RBCs and WBCs. They are released into the stream of blood whenever required.

The peripheral smear examination helps to:

• Compare the size, shape, and general appearance of WBCs along with determining its five different types and their relative percentages.

• Detects the size, shape, and color of the RBCs.

• Evaluates the number of platelets.

The number and the appearance of blood cells can be affected by a variety of diseases and conditions such as the smaller size of RBCs may indicate a type of anemia, increased number of WBCs may indicate infection or any other condition.