Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1993-08-02
1994-11-22
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
73 6166, G01D 534
Patent
active
053671570
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a device for rapidly performing a sedimentation-rate test, comprising an elongate lid-equipped vessel for receiving a given amount of blood, and a frame with a holder for said vessel which, when disposed in the frame, is rotatable in the vertical plane about an axis perpendicular to its longitudinal axis, and rotatable about its longitudinal axis.
The sedimentation-rate test is a blood test commonly used in medical check-ups. It is a non-specific test, but gives, when combined with Other tests, an idea of e.g. on-going inflammatory processes.
Today, the sedimentation-rate test is standardized by national and international organizations, such as the NCCLS, the ICSH and the WHO. In most cases, it is performed by letting a tube (vessel), which has a length of about 250 mm and an inner diameter of about 2.54 mm, be filled with a mixture of citrate and blood at room temperature to a height of 200 mm, and placing the tube in the vertical position for 60 min. Then, the sedimentation-rate is read as the decrease in height (nun) of the red blood column compared with the original height. The overall testing time is about 70-75 min, including the cooling of the blood to room temperature. The blood used in the sedimentation-rate test may be either venous or capillary blood.
Stein W: `Blutsenkungen in 10 Mlnuten-Verfahren` Med. Mschr 1949, 3, pp 919-921 describes a quick sedimentation rate test of common type used. In this method, the sedimentation tube is placed at an angle of 60.degree. to the vertical, and the sedimentation-rate value in mm/h can be read after 10 min. However, this method requires reading experience, and is not widely used. Norwegian Patent 153,508 discloses a modified version of the quick sedimentation rate test according to Stein. In the Norwegian method, which is used for simplifying the reading of a tilted sedimentation tube, the tube is, while turned a certain number of revolutions, erected to the vertical position where a conventional reading is performed.
When testing venous blood of which a few millimeters are available, a specimen is taken by means of a syringe, often filled with a suitable quantity of citrate, or a vacuum tube filled beforehand with citrate. The vacuum tube is highly advantageous in terms of hygiene, since the blood and the citrate thus are mixed in a tube where the proportion of blood to citrate is ensured by the vacuum present in the tube when the blood specimen is taken. In a standardized sedimentation tube design, the tube (vessel) is then filled with the solution of titrate and blood, as described earlier. In cases where the sedimentation rate is read directly from a vacuum tube with an inner diameter exceeding 3 mm, the vacuum tube is placed in the vertical position, and after the solution has been brought to room temperature with intense mixing in the vertical position, the sedimentation rate is read after 60 min in the manner described. When the sedimentation rate is read directly from short vacuum tubes in which the height of the blood column is less than 200 mm, a conversion scale is employed to give a sedimentation-rate numerical value equivalent to that obtained by the standardized method. In an article by B. HJalmarsson, published in Laboratoriet No. 6/85, a vacuum-tube system for sedimentation-rate tests is described, which employs a tube with an inner diameter of 9 mm. It appears from this article that the analysis takes at least 70 min when a vacuum tube is used, including the time required for mixing and bringing the solution to room temperature.
If capillary blood, e.g. taken from the fingertips, is used, only small quantities of blood are available. A special method is required when the capillary blood is diluted with a quantity of citrate corresponding to a dilution ratio of blood to citrate of 1/41, and the citrated blood is agitated and drawn up in a tube with a total volume which usually is less than 150 .mu.l. The inner diameter of a suitable tube then is in the order of 1 mm.
One object of the present invention is t
REFERENCES:
patent: 3199775 (1961-09-01), Drucker
patent: 3614434 (1971-10-01), Horwitz et al.
patent: 5133208 (1992-07-01), Ricci
Lilja Jan E.
Nilsson Sven-Erik
Hemocue AB
Nelms David C.
Nichols Steven L.
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