A client has been receiving cyanocobalamine (B12) injections for the past 6 weeks. Which laboratory finding indicates that the medication is having the desired effect? A. Neutrophil count of \(60 \%\) B. Basophil count of \(0.5 \%\) C. Monocyte count of \(2 \%\) D. Reticulocyte count of \(1 \%\)

Cyanocobalamin (B12) plays a vital role in DNA synthesis and red blood cell production. A deficiency in B12 may lead to pernicious anemia, which is characterized by immature red blood cells (megaloblasts) and a low red blood cell count. The laboratory values presented in this problem (neutrophil, basophil, monocyte, and reticulocyte counts) are different types of white blood cells and immature red blood cells.

Now, let's analyze each option to see which one represents the impact of cyanocobalamin treatment on the patient's blood count: A. Neutrophil count of \(60 \%\): Neutrophils are a type of white blood cell involved in the immune response and do not represent the impact of B12 injections. B. Basophil count of \(0.5 \%\): Basophils are another type of white blood cell involved in inflammatory response and would not indicate the impact of B12 injections. C. Monocyte count of \(2 \%\): Monocytes are another type of white blood cell that doesn't indicate any B12 deficiency-related blood abnormalities. D. Reticulocyte count of \(1 \%\): Reticulocytes are immature red blood cells and serve as an indicator of bone marrow's red blood cell production. An increase in reticulocyte count reflects a better production of red blood cells, which is directly related to B12 levels.

Based on the analysis in step 2, the correct answer is: D. Reticulocyte count of \(1 \%\) This laboratory finding shows that B12 injections are improving the red blood cell production, and therefore having the desired effect.