Reticulocyte Count Test

Blood is a precious fluid. Plasma, white blood corpuscles and red blood corpuscles are the three kinds of cells in the blood. The blood cells are normally made in the bone marrow. To know the level of red blood cells in the blood, reticulocyte count test is done.

Reticulocyte Count Test

Reticulocyte are immature red blood cells made by the bone marrow. Reticulocytes are in the blood for two days before developing into mature cells. Reticulocyte count test is done to determine if red blood cells are being made in the bone marrow at an appropriate rate. The count indicates how quickly reticulocytes are being produced and released by the bone marrow.

Need for Reticulocyte count test

Paleness, tiredness, weakness, shortness of breath, and/or blood in the stool are symptoms when doctors recommend Reticulocyte count test to:

• Assess the functioning of bone marrow i.e. if enough red blood cells are made by the bone marrow.
  
• Diagnose and distinguish the different kinds of anemia and the reasons for anemia, if it is due to fewer red bloods or due to great loss of red blood cells.
  
• Evaluate reasons for chronic bleeding and or/blood in the stool.
  
• Monitor progress after chemotherapy, bone marrow transplant, treatment for iron deficiency etc.
  
• Determine the degree and rate of increased number of RBCs and elevated hemoglobin (rare occurrence) and hematocrit.

Reticulocyte count test - Preparation

There isn't any specific preparation required before Reticulocyte count test. However, it is recommended to check with health care provider if any specific pre test preparation is needed. Those who have had a recent blood transfusion should inform the doctor. This can affect test results. Important information to be shared with the doctor is about medicines being taken. Women who are pregnant and mothers who are breastfeeding infants should talk to doctor before opting for the test.

Reticulocyte count test Method

The test result is available few hours after collecting blood or the next day. An elastic band is wrapped around the upper arm to stop the flow of blood. Sample of blood from the vein of the arm is taken. A drop of blood is placed on a slide, smeared, stained and is examined under a microscope. This is the manual method. Automated methods that allow for greater number of cells to be counted are most likely to replace the manual method.

Reticulocyte count test result Interpretation

The number of reticulocytes is compared to the total number of red blood corpuscles (RBC) and is reported as a percentage of reticulocytes.

Reticulocyte (%) = [Number of Reticulocytes / Number of total Red Blood Cells] X 100

In a healthy adult person, the normal range is 0.5% to 1.5%. In kids, the normal range is 3% to 6%. This is a stable percentage. The normal range may slightly vary.

High reticulocyte count suggests more red blood cells are being made by the bone marrow. This could be due to acute bleeding, chronic blood loss, hemolytic anemia, kidney disease and potentially a fatal blood disorder in the fetus or new born - erythroblastosis fetalis (Erythroblastosis Fetalis refers to a serious blood disorder in infants - Rh incompatibility disease and ABO incompatibility disease) or hemolytic disease. Also, the count increases post treatment for certain anemia like iron deficiency anemia, pernicious anemia, or folic acid deficiency anemia.

Erythroblastosis Fetalis refers to a serious blood disorder in infants - Rh incompatibility disease and ABO incompatibility disease. Low reticulocyte count suggests fewer red blood cells are being made by the bone marrow. This can be due to aplastic anemia or iron deficiency anemia. Other instances such as exposure to radiation, a chronic infection or due to intake of certain medicines (drug toxicity) can lead to low count.

The reticulocyte count increases temporarily during pregnancy. The count is high in newborns but within few weeks the count drops to adult levels. In case the result is abnormal more tests may be administered for further analysis.

Spherocytosis

Hereditary Spherocytosis is a genetic disorder characterized by red blood cells that are fragile and spherical in shape instead of the normal flat disk shape. The abnormal shape makes it difficult for red blood cells to pass through the spleen. The spleen's function is to purify the blood and safeguard the immune function by fighting against the potentially dangerous bacteria, viruses or other microorganisms in the blood. In case of Spherocytosis, the membrane of the red blood cells is defective lending it a spherical shape. When these defective blood cells pass through the spleen, they break and destroy causing premature death of the red blood cells. The shortage of blood cells gives rise to severe anemia. It is an inherited type of Hemolytic Anemia. A parent with the disease has a 50% chance of having a child with the disease. Spherocytosis is most common in people of northern European descent.

Symptoms

The symptoms can vary from mild to severe. In severe cases, the disorder may be found in early childhood. In mild cases it may go unnoticed until adulthood. Patients with Spherocytosis exhibit all the symptoms associated with anemia such as fatigue, irritability, shortness of breath and muscle weakness. They also appear pale and weak. In addition to these symptoms, Spherocytosis also causes enlarged spleen and jaundice with yellow skin and eyes. Jaundice occurs due to the elevated levels of serum bilirubin as the red blood cells are destroyed within the body. Excess bilirubin, sometimes, also results in in the gallbladder. These stones may cause pain, infection or may block the tubes that lead out of the gallbladder.

Diagnosis

Family history is checked for hereditary factor and the abdomen has to be checked for enlarged spleen. Following blood tests may be performed to support the clinical examination:

• CBC or complete blood count test to check for anemia.
  
• The Reticulocyte Count Test is performed to measure the new and immature red blood cells produced in the bone marrow. The reticulocyte count is usually higher in cases of Spherocytosis.
  
• Osmotic Fragility Test is performed to measure the fragility of the red blood cells. This involves taking a blood sample and suspending in a salt solution and then measuring the destruction and fragility of the cells.
  
• Coombs Test to measure the antibodies in the blood.
  
• Blood test to check for bilirubin levels.

Treatment

Splenectomy is the most definitive treatment for hereditary Spherocytosis. By removing the spleen, red blood cells are prevented from damage and are allowed to stay alive for a longer duration. However, removing a spleen makes the patient susceptible to infections for a lifetime. Hence patients need to take penicillin (or another antibiotic) for the rest of their lives. Immunization against pneumococcal and meningococcal infections is also prescribed. In case of severe anemia, blood transfusion is advised.