What is the correct order of components when labeling RBCs with radiochromium?

The correct order for labeling red blood cells (RBCs) with radiochromium involves starting with the patient’s blood, followed by the addition of radiochromium, and then incorporating ascorbic acid. This sequence is essential to ensure that the radiochromium effectively binds to the RBCs for imaging or diagnostic purposes.

By beginning with the patient’s blood, the red blood cells are present in the environment where the labeling will occur. The subsequent addition of radiochromium allows for the isotopic labeling of these cells. Radiochromium is a radiotracer that binds to the hemoglobin in red blood cells. Finally, ascorbic acid is included to act as a reducing agent, helping to maintain the reduced state of the radiochromium, enhancing the stability of the label on the RBCs, and preventing the oxidation that could reduce the effectiveness of the labeling process.

Using this order ensures optimal conditions for radiochromium binding to RBCs, which is crucial for accurate imaging and diagnostics in nuclear medicine.