A sample cell apparatus for use in spectroscopic determination of an analyte in a body fluid sample, the sample cell apparatus comprising: a first plate member made from an optically clear material; a second plate member made from an optically clear material and opposing the first plate member; a first surface of the first plate member facing the second plate member, the first surface comprising a first well portion, a first seal channel portion adjacent to the first well portion, and a first abutment surface outside of the first well portion and outside of the first seal channel portion (12, 13); and a second surface of the second plate member facing the first plate member, the second surface comprising a second well portion aligned with the first well portion to form a sample chamber, a second seal channel portion aligned with the first seal channel portion (12, 13) and adjacent to the second well portion, and a second abutment surface outside of the second well portion and outside of the second seal channel portion and aligned with the first abutment surface, the second abutment surface configured to abut the first abutment surface; wherein the first well portion has a fixed depth relative to the first abutment surface and wherein the second well portion has a fixed depth relative to the second abutment surface; one or more spring members configured between the first plate member and the second plate member and configured to urge the first plate member away from the second plate member; a floating seal extending into the first seal channel portion and the second seal channel portion, the floating seal compressed transversely between sidewalls of the first seal channel and the second seal channel, the floating seal defining a periphery of the sample chamber; a fluid inlet path extending through the first plate member the second plate member into the sample chamber; and a fluid outlet path extending through the first plate member or the second plate member i into the sample chamber. a first plate member made from an optically clear material; a second plate member made from an optically clear material and opposing the first plate member; a first surface of the first plate member facing the second plate member, the first surface comprising a first well portion, a first seal channel portion adjacent to the first well portion, and a first abutment surface outside of the first well portion and outside of the first seal channel portion (12, 13); and a first well portion, a first seal channel portion adjacent to the first well portion, and a first abutment surface outside of the first well portion and outside of the first seal channel portion (12, 13); and a second surface of the second plate member facing the first plate member, the second surface comprising a second well portion aligned with the first well portion to form a sample chamber, a second seal channel portion aligned with the first seal channel portion (12, 13) and adjacent to the second well portion, and a second abutment surface outside of the second well portion and outside of the second seal channel portion and aligned with the first abutment surface, the second abutment surface configured to abut the first abutment surface; wherein the first well portion has a fixed depth relative to the first abutment surface and wherein the second well portion has a fixed depth relative to the second abutment surface; a second well portion aligned with the first well portion to form a sample chamber, a second seal channel portion aligned with the first seal channel portion (12, 13) and adjacent to the second well portion, and a second abutment surface outside of the second well portion and outside of the second seal channel portion and aligned with the first abutment surface, the second abutment surface configured to abut the first abutment surface; wherein the first well portion has a fixed depth relative to the first abutment surface and wherein the second well portion has a fixed depth relative to the second abutment surface; one or more spring members configured between the first plate member and the second plate member and configured to urge the first plate member away from the second plate member; a floating seal extending into the first seal channel portion and the second seal channel portion, the floating seal compressed transversely between sidewalls of the first seal channel and the second seal channel, the floating seal defining a periphery of the sample chamber; a fluid inlet path extending through the first plate member the second plate member into the sample chamber; and a fluid outlet path extending through the first plate member or the second plate member i into the sample chamber.