A negative or normal level does not rule out underlying neoplasm.
The concentrations of tumour marker assays determined by different methods or different manufacturers are not comparable and cannot be used interchangeably. Follow-up serial samples done by different methods or laboratories can be misleading.
Serum samples from patients who have received preparations of mouse monoclonal antibodies for diagnosis or therapy may contain human anti-mouse antibodies (HAMA). These antibodies may cause false positive or false negatives when tested with our MEIA assays. Indicate if your patient has received diagnostic or therapeutic antibodies (dose and date).
Results denoted "assay under investigation" mean the tumour marker is being investigated and evaluated for use by the TML. These assays are available on a limited basis and there are no reference intervals (normals) available other than those recommended by the assay manufacturers and the guidelines from the relevant literature. The lab requires a detailed history of these patients in order to properly evaluate the assay results, your cooperation is truly appreciated.