Rapid test for diagnosis of bacterial infections in neonates

1 . A method for point-of-care diagnosis and bedside stratification of and septic processes in a blood or serum sample of a neonate, comprising

diluting a defined amount of sample in a defined amount of buffer having a pH between 5.0 and 5.7, which buffer does not induce an uncontrolled release of proteins from blood cells, granulocytes, monocytes, mast cells or leukocytes and allows for a quantitative flowthrough immunobinding assay of the S100 protein analytes,

performing one or more flowthrough immunobinding assays at a pH between 5.0 and 5.7 for quantitative or semi-quantitative detection and measurement of at least two proteins of the S100 family of calcium-binding proteins, including at least separate and parallel quantitative or semi-quantitative determinations of S100A12 and calprotectin (S100A8/A9), each yielding an independent measurement result;

wherein the buffer comprises

20-30 g trisodium citrate,

2.0-5.0 g citric acid,

2.0-5.0 g monobasic sodium phosphate (NaH 2 PO 4 ),

and mixed with the blood component in a ratio of about 1:5 to 1:10.

2 . The method of claim 1 , comprising

employing two separate flowthrough immunobinding assays in one housing adapted to produce visual zones indicating the presence and content of the analytes (T) in said sample and respective control zones (C).

3 . The method of claim 1 , further employing a portable processor device comprising a digital camera, a source of light and a processor configured to process digital images captured by said camera and to represent a diagnostic result.

4 . The method of claim 1 , further comprising the use of a blood sampling system which contains or is coated with an acidified preservative buffer of a pH between 5.0 and 5.7.

5 . The method of claim 1 , wherein the one or more lateral flow tests comprise a size-exclusion technique, comb, mesh, weir-type filter structure, microporous fleece or fabricated porous filter membrane for retention of particulate blood components and blood cells from the liquid portion.

6 . A method of treating neonates suffering from an inflammatory reaction of unknown etiology comprising

identifying neonates suffering from an inflammatory reaction of unknown etiology by

mixing a predefined amount of bodily fluid, capillary blood or whole blood with a predefined amount of acidified buffer, having a pH in the range from 5.0 to 5.7 and a functional amount of blood preservative anticoagulant to form an acidified mixture;

applying predefined amounts of the acidified mixture onto the application zones of one or more lateral flow immunoassays and performing a lateral flow immunochromatography for separate and parallel determination of the presence and content of S100A12 and of calprotectin, each yielding an independent measurement result; and

evaluating the amounts of both S100A12 and calprotectin in the visual zones with the amounts present in samples taken from healthy subjects, where increased amounts of S100A12 and calprotectin are present and indicate the presence of a septic process, and

treating the identified affected neonates with antibiotics.

7 . The method of claim 6 , wherein a photographic image of the lateral flow immunoassays is taken, and the diagnostic result is determined on basis of a digital photographic image using data of the visible zones and calibration data provided by the manufacturer.

8 . The method of claim 6 , comprising a quantitative or semi-quantitative determination of markers of the innate immune system activation.

9 . The method of claim 6 , comprising:

(a) taking a color digital image of the lateral flow immunoassay using a portable processor device comprising a digital camera, a source of light and a processor, wherein said processor is configured to process digital images captured by said camera and to represent an analytical result;

(b) analyzing digital image for the location of the region of interest of said one or more lateral flow tests and for the amounts of signal.

10 . The method of claim 6 for simultaneous detection of S100A12 and calprotectin, comprising two parallel lateral flow immunoassays having in fluid communication

(i) a sample pad at the proximal end for receiving the sample, followed by

(ii) a size-exclusion technique, comb, mesh, weir-type filter structure, microporous fleece or fabricated porous filter membrane for retention of particulate blood components and blood cells from the liquid portion;

(iii) a conjugate pad containing mobile labeled immunoreactants which bind to the analyte,

(iv) a membrane with porous separation material thereon, and

(v) a water-adsorptive wicking pad at the distal end,

wherein the separation membrane defines a proximal test zone containing immobilized capture molecules which bind to either analyte and a distal control zone for receiving mobile labeled immunoreactants.

11 . The method of claim 1 , wherein the blood or serum sample is capillary blood.

12 . The method of claim 6 , wherein the blood or serum sample is capillary blood.