BIOEQUIVALENT ALLERGY UNITS

[gschadow]

Requested for FDA/CBER in order to support biologic structured product labeling:

BIOEQUIVALENT ALLERGY UNITS (typically abbreviated "BAU") - a biological potency unit assigned to several standardized allergenic extracts, following in-vitro comparison of the test extract to an FDA CBER reference standard. The FDA CBER reference standard is assigned a specific BAU unitage based on quantitative skin testing in allergic individuals.

See also #18 and #19

[gschadow]

The definition is not sufficient to establish this notion as a unit.

This being an in-vitro measurement using a reference standard makes it eligible as any other arbitrary unit such as I.U.

Contrast this with #17, which is going to be very hard.

[gschadow]

I meant "contrast this with #18" not 17.

[gschadow]

Submitter states:

"AU and BAU are both based on FDA reference standards and, ultimately, on titration skin testing by the ID50EAL method. I have attached a reference on that method, on the BAU unitage, and on the older AU unitage."

[gschadow]

Biological Standardization based on Quantitative Skin Testing

[gschadow]

[BAU] see comment under #18. Provisionally accepted.

[gschadow]

While applying this, it is clear that this is still not defined as a unit.

But the Turkeltaub paper does provide a lot of detail for some metrologic formalization of what is going on.

This method needs to be further investigated to determine a quantitative model which relates that would relate 1 BAU with a standardized amount of substance of the standardized allergenic protein. The situation is not unlike the titer and is not worse than for many of the arbitrary units listed already. In a future revision a stronger formalized metrologic model will be added to this specification.