Exact Answer: 24 Hours
The human body does a lot of work daily. The muscular system, skeletal system, nervous system, digestive system, etc., play an important role in our lives. The brain and heart being the two main organs of the body. When oxygen reaches these two organs, these organs function well. The carrying of oxygen and nutrients to different parts of the body is done by blood.
About 70 percent of a human body is covered by water, out of which, the most is the blood. Sometimes due to some medical problems or accidents, there is blood loss. In those cases, a blood transfusion is required to save that person. CBC is performed to measure blood cell count and it can be only taken after 24 hours of blood transfusion, to check that everything is in order or not.

How Long After Transfusion CBC?
Type | Time |
Small Transfusion | < 24 Hours |
Large Transfusion | > 24 Hours |
A blood transfusion is a medical situation. It happens when a person loses a large amount of blood from his/her body due to unforeseen events. In that situation, a doctor transfers blood from another healthy person or from the blood bank to help the person survive. The blood type of the donor should be the same as the victim and it should be checked that the donor should be completely healthy.
After a blood transfusion, a person needs rest as he has been through a lot. The doctors keep the patient under observation for at least 24 hours to see whether the blood transfusion is successful or not. After everything is done, the CBC is performed. CBC means complete blood count, it mainly consists of a few medical tests to check about the cells in the patient’s body. Haemoglobin, hematocrit, blood platelets, and red and white blood cells, everything is found by doing the tests.
It is very important to do a CBC. It is so because, even if blood transfusion is complete, there is no guarantee that the patient will have the normal rate of blood cells and platelets. Less or more of these can create other medical complications. To avoid such situations, a CBC is performed. It is advised to stay well hydrated after the transfusion.
Why A Transfusion CBC Takes Long?
In general, a CBC is not performed after a long time after a transfusion takes place. A person can feel better just after the transfusion, as blood loss makes a person weak and lose consciousness while regaining blood can prevent those circumstances. A large blood transfusion takes time to happen and the CBC is delayed, but a small amount can let the doctors perform an immediate CBC to catch up on the health of the patient.
After a transfusion is done, a person can follow a normal diet without any restrictions, but a few medications are given. Sometimes, a person may feel cold after a transfusion, in those case, a blanket or sweater should be provided to the victims. The person can return to their daily life and continue their work. Performing a CBC is not time-consuming but it differs in emergency and non-emergency cases.
Not only after transfusions but CBCs can be done whenever a person feels to. A lot of diseases can happen to a person with low hemoglobin and low platelet count, as these defend the body against foreign particles. CBCs can be done to keep the components of blood in check, to diagnose medical conditions, to observe a medical condition, and to monitor any kind of medical treatments.
Conclusion
After performing a transfusion, a CBC is a must just like taking medicines after being diagnosed with a disease. Moreover, a person should keep track of his or her red and white blood cells with platelets and the concentration of hemoglobin. When the level of hemoglobin becomes low, the chances of having anemia increase. Low red blood cells can be replenished by having food containing iron.
Performing a transfusion and conducting a CBC is not the end. Even after everything is done, it is very important to follow the guideline given by the doctor to lead a healthy and safe life.
References
- https://www.nejm.org/doi/full/10.1056/NEJM199902113400606
- https://www.sciencedirect.com/science/article/pii/S1089947203000042

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