Test element analysis system for the analytical investigation of a sample,
in particular of a body liquid of human beings or animals, comprising
test elements (2) with a carrier film (5) and a test field (7) fixed to
the flat side (6) of the carrier film (5), the test field (7) containing
a reagent system the reaction of which with the sample (21) leads to an
optically measurable change in the detection zone (24) which is
characteristic for the analysis, and an evaluation instrument with a
measuring device for measuring the optically measurable change. In order
to obtain a very high measuring accuracy and an easy handling at the same
time, the carrier film (5) of the test element (2) comprises a light
guide layer (26), the detection zone (24) of the test field (7) is in
optical contact to the light guide layer (26) in a coupling out zone
(33), enabling the coupling out of light from the light guide layer (26)
to the detection zone (24), the primary light (29) of the light emitter
(16) is coupled into the entry surface (31) in the light guide layer (26)
in such a manner that a light guide section (32) of the light path of the
primary light (29) runs between the entry surface and the detection zone
(24) inside the carrier film (5), and the secondary light is reflected
from the detection zone (24) into the light guide layer (26) in such a
manner that a light guide section (34) of the light path of the secondary
light runs between the detection zone (24) and the detector (17) inside
the light guide layer (26).