Which of the following statements regarding paraproteins is true?

The statement that oligoclonal banding is seen in the cerebrospinal fluid (CSF) of greater than 90% of multiple sclerosis cases is accurate. Oligoclonal bands refer to a specific pattern of multiple bands of immunoglobulins observed in the CSF when an electrophoresis test is performed. Their presence indicates a localized immune response in the central nervous system, commonly associated with conditions like multiple sclerosis. In over 90% of patients with multiple sclerosis, the presence of these oligoclonal bands supports the diagnosis, as they show that there is an increased production of antibodies in the CSF that is not present in the serum.

The other statements are not correct. The Bence-Jones protein heat test is a diagnostic tool for identifying light chains in urine, but it is not definitive for confirming monoclonal light chains due to potential false positives. Light chains found in urine may not always originate from monoclonal sources, as they can be produced as part of a polyclonal response as well. Lastly, the positioning of immunoglobulin bands is determined by their charge; often, the IgG band precedes IgA in an electrophoresis gel, making the claim about their relative positions inaccurate