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.