Final answer:
The nurse should report to the provider the low white blood cell (WBC) count of 3,000/mm³, as it can increase the risk of infection and may require adjustments in chemotherapy or additional supportive care.
Step-by-step explanation:
The laboratory value that the nurse should report to the provider is c) White blood cell count 3,000/mm³. Chemotherapy is known to cause a reduction in white blood cells, critical components of the immune system, and a white blood cell (WBC) count of 3,000/mm³ is considered low. The normal range for WBC is typically 3.5 to 11 x 10⁹ cells/L. Such a reduction can put the patient at risk of infection and could be an indication to either delay chemotherapy or intervene with supportive care to manage the risk of infection. The other listed lab values, including hemoglobin of 12 g/dL, a platelet count of 150,000/mm³, and a serum potassium level of 4.2 mEq/L, are within normal ranges for a child and would typically not be a concern.