Test strip for determining concentration of multiple analytes in a single fluid sample
View Patent ↗A multilayer test strip that measures concentrations of multiple analytes from a single whole blood sample. The test strip includes a test matrix of several layers held together in constant contact by a test strip holder. The invention is characterized in that it has no moving parts, which is made possible by the novel use of an elongate disbursement layer that spreads blood throughout its entire length, despite having layers with known wicking properties adjacent to and in contact with it. Since the invention relies primarily on a vertical flow format, the test strip is advantageously quite compact. With a single 35 microliter sample of blood applied thereto, the novel test strip can provide readings of total cholesterol, HDL cholesterol and triglycerides. From these, LDL can be calculated, thereby providing a full “lipid panel.” Other analytes such as glucose and ketones may be included in the test strip in addition to or in lieu of one or more of the other analytes.
1. Apparatus for measuring concentration of multiple analytes in a whole blood sample, comprising:
a test matrix comprising:
an elongated porous disbursement layer;
at least one blood separation layer adjacent to the bottom surface of said disbursement layer;
at least two vertically aligned stacks spaced apart and adjacent to the bottom surface of said at least one blood separation layer;
wherein a first one of said vertically aligned stacks includes multiple layers, said multiple layers including a reagent and a chromagen, said multiple layers of said first stack not including a blank layer, and a second one of said vertically aligned stacks includes a blank layer, said blank layer having a thickness suitable for maintaining said stacks at substantially the same total thickness, said blank layer containing neither any reagents nor chromagen, said second stack including a chromagen layer below said blank layer;
said apparatus further comprising a test strip holder having top and bottom portions sandwiching said test matrix therebetween, said top portion of said test strip holder having a sample application window exposing a top surface of said disbursement layer, and said bottom portion of said test strip holder having at least one test reading window through which bottom surfaces of said first and second stacks can be read.
2. The apparatus of claim 1 , wherein said sample application window is positioned within a periphery defined by said stacks.
3. The apparatus of claim 1 , wherein the bottom surfaces of said stacks are substantially coplanar.
4. The apparatus of claim 1 , wherein said blood separation layer comprises a glass fiber matrix.
5. The apparatus of claim 1 , wherein said multiple layers in said first one of said stacks comprise:
a fractionation layer containing a precipitating agent for non-HDL cholesterol, said fractionation layer adjacent to and in contact with the bottom surface of said at least one blood separation layer; and
a reaction layer adjacent to and in contact with the bottom surface of said fractionation layer, said reaction layer containing a cholesterol determining agent, whereby said first stack measures concentration of HDL.
6. The apparatus of claim 5 , wherein said blank layer in said second one of said stacks is adjacent to and in contact with the bottom surface of said at least one blood separation layers, and a second reaction layer containing a cholesterol determining agent is adjacent to and in contact with the bottom surface of said blank layer, whereby said second stack measures total cholesterol concentration.
7. The apparatus of claim 6 , wherein a third one of said stacks comprises a second blank layer adjacent to and in contact with the bottom surface of said at least one blood separation layer and a third reaction layer containing a triglycerides determining agent adjacent to and in contact with the bottom surface of said second blank layer, whereby said third stack measures triglycerides concentration.
8. The apparatus of claim 6 , wherein a third one of said stacks comprises a second blank layer adjacent to and in contact with the bottom surface of said at least one blood separation layer and a third reaction layer containing a glucose determining agent adjacent to and in contact with the bottom surface of said second blank layer, whereby said third stack measures glucose concentration.
9. The apparatus of claim 1 , wherein said at least one blood separation layer comprises a plurality of blood separation layers, each said blood separation layer of said plurality corresponding to one of said stacks and being vertically aligned therewith.
10. The apparatus of claim 1 , wherein said at least one blood separation layer comprises a single blood separation layer having dimensions substantially the same as said disbursement layer.
11. The apparatus of claim 1 wherein said sample application window comprises a single opening through which fluid from said blood can be applied to said stacks.