VACUUM TUBE FOR TAKING BLOOD SAMPLES, CONTAINING AN ANTICOAGULANT

Abstract: Vacuum tube for taking blood samples, containing an anticoagulant and 0.005 - 0.1 ml per ml blood of formaldehyde or calomel diluted with distilled water in the ratio 1:30.

Description: VACUUM TUBE FOR TAKING BLOOD SAMPLES, CONTAINING AN _- a * ANTICOAGULANT . The invention relates to a vacuum tube for taking 5 blood samples, containing an anticoagulant. The usual anticoagulant in such tubes comprises ethylenediaminetetra-acetic acid, EDTA. The tube is used for taking blood samples which are to be used for determining the number of blood cells of different 10 kinds. If the blood is left in the tube for a relative long time (an hour or some hours) at room temperature, the blood cells will change so that measurement cannot be made with the certainty and accuracy which are generally required, by the sample being introduced into 1 5 an analysis apparatus or a microscope. It is endeavoured to extend the storing time by storing the sample at a reduced temperature, +10 C, and as a consequence thereof the leucocytes can be maintained fairly intact, but this is not true as far as the trombocytes are 20 concerned, which on the contrary are damaged during storing at low temperature. The leucocytes can be saved for a longer time by applying the blood sample to a microscope slide for subsequent analysis, but this requires knowledge and 25 experience which most often is not to be found with the personnel taking the blood sample, and the consequence thereof is that the sample most often cannot be used for obtaining a reliable result. The alternative is that the sample is handed over to a laboratory in the test tube, 30 but then the time factor mentioned above has to be considered. Thus, it is important to analyse the blood sample which has been taken, without delay, but this may be difficult and, moreover, it is not known how old a sample is and then ' it is not possible to adjust the 35 result of the analysis with consideration thereof. The purpose of the invention is to obtain an extended life of the blood sample taken in a vacuum tube of the kind referred to above, ' and for this purpose the vacuum tube has obtained the characteristics according to claim 1. Vacuum tubes with an anticoagulant comprising EDTA are available on the market with different amounts of anticoagulant and for taking varying amounts of blood. Thus, the amount of EDTA can range from 0.054 ml to 0.1 ml and the intended amount of blood which is to be collected in the vacuum tube can range from 3 ml to 10 ml. The EDTA can be replaced by sodium citrate as the coagulant. In the tube of the invention, a certain amount of formaldehyde is added, comprising a water solution containing 30-40% formaldehyde, mixed with distilled water in the ratio 1:30. The amount of diluted- formaldehyde then amounts to 0.005 ml - 0.1 ml, preferably 0.02 ml - 0.06 ml, per ml blood to be collected in the tube. Generally, it can be stated that the amount of diluted formaldehyde per ml blood should be at a lower limit at which there is obtained an alkalization of the blood sample, and at an upper limit, at which the blood cells in the blood sample will shrink. The formaldehyde in the vacuum tube can be replaced by calomel (percipitated mercury chlorure) diluted with distilled water in the ratio 1:30 and in an amount within the same limits mentioned for formaldehyde. The blood sample taken in a vacuum tube of the invention is characterized by a longer storing time and an extended temperature durability than blood samples which have been taken in conventional vacuum tubes containing an anticoagulant only. This is illustrated by the accompanying diagram which discloses the number of leucocytes existing in a sample which has been stored at different temperatures with and without the addition of formaldehyde, at different times after the blood sample having been taken.

Claims: CLAIMS 1. Vacuum tube for taking blood samples, containing an anticoagulant, c h a r a c t e r i z e d in that the vacuum tube also contains 0.005 - 0.1 ml per ml blood of formaldehyde or calomel diluted with distilled water in the ratio 1:30. 2. Vacuum tube as claimed in claim 1, c h a r a c t e r i z e d in that the amount of diluted formaldehyde or calomel, respectively, amounts to 0.02 - 0.06 ml per ml blood.

Inventors: HOOGERVORST NICOLAAS WOUTERUS, SVENSSON JAN AXEL, HOOGERVORST, NICOLAAS, WOUTERUS, WILHELMUS, SVENSSON, JAN, AXEL
Applicants: HOOGERVORST NICOLAAS WOUTERUS, SVENSSON JAN AXEL, HOOGERVORST, NICOLAAS, WOUTERUS, WILHELMUS, SVENSSON, JAN, AXEL
Application year: 1985
Main classification: G01N33
IPC codes: G01N33