Appeal No. 1996-3973
Application No. 08/048,657
intermediate porous glass fiber disc 20; a lower porous glass fiber disc 22; a porous filter
membrane 26 (e.g., a cellulose acetate membrane); and a transparent film membrane 30, wherein
a first reagent is absorbed on discs 18, 20 and 22 and a second reagent is freeze-dried on the inner
surface of membrane 30 (Fig. 3; col. 4, lines 38-61). EXAMPLE 3 (col. 6) illustrates a test
device for determining hexokinase wherein the upper glass fiber discs are impregnated with
NADP, G-6-P, magnesium acetate, PMS and NBT (an indicator reagent which reacts to form a
detectable formazan dye), while the lower transparent film membrane is coated with G-6-PDH,
dextran and, if necessary, hexokinase.
The examiner states “[t]he claims differ from Daffern above in that the claims include
multiple layers with a single aligned aperture” and concludes that it would have been obvious to
one of ordinary skill in the art “to employ the multiple layer features of the test strip apparatus of
Moyer in the test strip of Daffern because related types of reactions are performed by the test
strips of both references” (answer, page 5). According to the examiner, “the teachings of the
references were clearly in the public domain and one of ordinary skill in this art known of these
references could have selected as the Appellants have done” (answer, page 11).
However, the examiner has not pointed out where either Daffern or Moyer discloses or
suggests the specific juxtaposition of (i) an apertured inert backing layer overlying (ii) a one or
two layered “reactive unit” comprising a spreading agent and an analyte-reactive reagent and (iii)
an indicator layer comprising an indicator reagent impregnated into a porous substrate. Both
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