What characteristic peak is typically observed on a serum protein electrophoresis (SPEP) of a patient with multiple myeloma?

In patients with multiple myeloma, the serum protein electrophoresis (SPEP) typically reveals a characteristic peak known as the "M-spike." This peak represents an abnormal increase in monoclonal immunoglobulin produced by malignant plasma cells. It is indicative of the proliferation of a single clone of plasma cells that secrete a uniform type of antibody, often seen in conditions like multiple myeloma. The presence of the M-spike is critical for diagnosis and is used to monitor disease progression and response to therapy.

The other choices do not correspond to findings typically associated with multiple myeloma. For instance, U-spike, H-spike, and V-spike are not established terms in the context of SPEP findings related to plasma cell dyscrasias or multiple myeloma. Thus, the correct identification of the M-spike is essential when diagnosing and monitoring this particular oncological condition.