Method for improving quality and functionality of filter paper suitable for collecting biological samples

Abstract

A method for diminishing variation between and/or within individual sheets of filter papers which are suitable for collecting samples of biological material, e.g. blood, is described. The method includes at least one of the following: subjecting the sheets of filter paper to gaseous substance containing at least 30 grams water per cubic meter and/or wetting the sheets of filter paper with water and subsequently drying the sheets of filter paper. According to tests, the above-described treatment significantly reduces the undesirable variation between results analyzed from sheets of filter paper and impregnated with same biological material for test purposes.

Claims

1. A method for treating filter paper, the method comprising: subjecting sheets of the filter paper to a gaseous substance containing at least 30 grams water per cubic meter, and/or wetting the sheets of filter paper with water and subsequently drying the sheet of filter paper, wherein variation between the sheets of the filter paper is diminished, the filter paper is configured for collecting samples of biological material by impregnation for a purpose of measuring analytes quantitatively and/or qualitatively from the biological material, and a count number 100,000 obtained with a photo detector, which is inversely proportional to an activity of the analyte being measured, is less than 1.

2. The method according to claim 1, wherein the gaseous substance is moist air in which there is at least 30 grams water per cubic meter.

3. The method according to claim 1, wherein the sheets of filter paper are subjected to steam having temperature at least 100 C.

4. The method according claim 3, wherein the temperature of the steam is at least 120 C.

5. The method according to claim 3, wherein the sheets of filter paper are subjected to the steam for a time period of at least 15 minutes.

6. The method according to claim 4, wherein the sheets of filter paper are subjected to the steam for a time period of at least 15 minutes.

7. The method according to claim 1, wherein the biological material is blood.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The exemplifying embodiments of the invention and their advantages are explained in greater detail below in the sense of examples and with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a histogram of results measured in an example case in which blood was impregnated into seven different sheets of filter paper from different filter paper batches,

(3) FIGS. 2a and 2b show flow charts of methods according to exemplifying embodiments of the invention for diminishing variation between and/or within individual sheets of filter paper which are suitable for collecting samples of biological material,

(4) FIGS. 3a and 3b show flow charts of methods according to exemplifying embodiments of the invention for handling biological material with the aid of filter paper, and

(5) FIG. 4 shows a histogram of results measured in an example case in which blood was impregnated into seven different sheets of filter paper taken from the same filter paper batches as in the example case of FIG. 1 and furthermore treated with a method according to an exemplifying embodiment of the invention; for the purpose of comparison, FIG. 4 shows also the histogram of the results shown in FIG. 1.

(6) FIG. 1 was already explained in conjunction with the description of the related prior art in the Background-section of this document.

DESCRIPTION OF THE EMBODIMENTS

(7) FIG. 2a shows a flow chart of a method according to an exemplifying embodiment of the invention for diminishing variation between and/or within individual sheets of filter paper which are suitable for collecting samples of biological material. The method comprises subjecting, in phase 201, the sheets of filter paper to gaseous substance containing at least 30 grams water per cubic meter. More preferably, the gaseous substance contains at least 40 grams water per cubic meter, and yet more preferably, the gaseous substance contains at least 50 grams water per cubic meter, and still more preferably, the gaseous substance contains at least 70 grams water per cubic meter. The gaseous substance can be, for example, moist air in which there is at least 30 grams water per cubic meter.

(8) In a method according to an exemplifying embodiment of the invention, the sheets of filter paper are subjected to steam having temperature at least 100 C., or more advantageously at least 120 C. The sheets of filter paper may be subjected to the steam for a time period of e.g. at least 15 minutes.

(9) FIG. 2b shows a flow chart of a method according to another exemplifying embodiment of the invention for diminishing variation between and/or within individual sheets of filter paper which are suitable for collecting samples of biological material. The method comprises wetting, in phase 202, the sheets of filter paper with water and subsequently, in phase 203, drying the sheets of filter paper.

(10) FIG. 3a shows a flow chart of a method according to an exemplifying embodiment of the invention for handling biological material with the aid of filter paper. The method comprises subjecting, in phase 301, a sheet of filter paper to gaseous substance containing at least 30 grams water per cubic meter, and subsequently in phase 304, impregnating at least one sample of the biological material into the sheet of filter paper. The biological material can be, for example, blood.

(11) FIG. 3b shows a flow chart of a method according to another exemplifying embodiment of the invention for handling biological material with the aid of filter paper. The method comprises, in successive phases 302 and 303, wetting a sheet of filter paper with water and drying the sheet of filter paper, and subsequently in phase 304, impregnating at least one sample of the biological material into the sheet of filter paper.

(12) A method according to an exemplifying embodiment of the invention further comprises measuring an analyte quantitatively and/or qualitatively from the biological material, e.g. blood, impregnated into the sheet of filter paper.

(13) In a method according to an exemplifying embodiment of the invention, activity and/or concentration of the analyte is measured from the biological material, e.g. blood, impregnated into the sheet of filter paper.

(14) In a method according to an exemplifying embodiment of the invention, the measuring of the analyte from the biological material, e.g. blood impregnated into the sheet of filter paper, is carried out as a fluorescence measurement. It should be, however, noted that methods according to various embodiments of the present invention are applicable also with various other measuring methods such as, for example, absorbance, time resolved fluorescence, luminescence, mass analysis.

(15) A method according to an exemplifying embodiment of the invention comprises measuring activity of the biotinidase enzyme from blood impregnated into the sheet of filter paper.

(16) FIG. 4 shows a histogram 401 of results measured in an example case in which blood was impregnated into seven different sheets ST1-ST7 of filter paper that had been treated with a method according to an exemplifying embodiment of the invention. In this exemplifying case, the treatment was autoclavation, i.e. subjection the sheets ST1-ST7 of filter paper to high pressure saturated steam at 120 C. or more for a time period of typically 15-20 minutes. The sheets ST1-ST7 of filter paper have been taken from the same filter paper batches as the untreated sheets S1-S7 of filter paper used in the example case illustrated in FIG. 1. For the purpose of comparison, FIG. 4 shows also the histogram 402 of results that are shown in FIG. 1 and that relate to the corresponding untreated sheets S1-S7 of filter paper. The vertical axis of the histograms 401 and 402 shown in FIG. 4 is the count number obtained with a photo detector. The count number is inversely proportional to the activity of the analyte that is measured. In this example case, the analyte that is measured is biotinidase.

(17) The specific examples provided in the description given above should not be construed as limiting. Therefore, the invention is not limited merely to the exemplifying embodiments described above.