For cell-based immunoassays (CBA) such as anti-MOG (myelin oligodendrocyte glycoprotein), are results reporting a change from medium to high levels of antibodies clinically significant?

MitogenDx detects anti-MOG by a cell-based immunofluorescence assay (CBA) where there is subjective, semi-quantitative interpretation of the intensity of immunofluorescence staining at a pre-set sample dilution. Therefore, there is no “numerical value” that is interpolated for these test results. Some laboratories perform CBA using a “flow system” where fluorescence intensity can be quantitated but the challenge becomes interpretation of numerical values that represent a clinically significant change?

In the past, we also reported the results as 0 (normal range/no staining visible); 1+ distinctive staining seen but of low intensity; 2-3+ medium and 4+ high intensity. MitogenDx simplified these results nomenclature to “normal” (negative), “low”, “medium” and “high” results.

In general, using quality assessment approaches inter-test variability (i.e. technical’ variability as one factor) does not change a result from one classification to another.

Hence, a change from one class to another (“medium” to “high” or “low” to “medium”) is regarded as quantitively significant.

Any changes in these semi-quantitative results should take into consideration therapeutic modalities (B cell modulators) used and why it would be expected that values would or would not be unchanged.

These considerations may be moot because it has been reported that variations of anti-MOG titers do not necessarily reflect clinical status. (1)