EP-4737910-A1 - AUTOMATIC ANALYSIS DEVICE

EP4737910A1EP 4737910 A1EP4737910 A1EP 4737910A1EP-4737910-A1

Abstract

There is provided an automatic analyzer that is capable of avoiding the occurrence of analysis failures due to a shortage of the remaining amount of a liquid by directly acquiring the remaining amount of the liquid in a vessel. For the purpose of the above, an automatic analyzer includes a probe that aspirates a liquid in a vessel, and an electrostatic capacitance measuring mechanism that measures an electrostatic capacitance across the probe and the liquid housed in the vessel. In the automatic analyzer, the automatic analyzer includes a liquid amount calculation unit that calculates an amount of the liquid based on an electrostatic capacitance value measured by the electrostatic capacitance measuring mechanism when the probe contacts the liquid housed in the vessel.

Inventors

TANAKA, SHINYA
FUNAHASHI, RYOSUKE
NISHIGAKI, KENICHI

Assignees

HITACHI HIGH-TECH CORPORATION

Dates

Publication Date: 20260506
Application Date: 20240619

Claims (8)

An automatic analyzer comprising: a probe that aspirates a liquid in a vessel; and an electrostatic capacitance measuring mechanism that measures an electrostatic capacitance across the probe and the liquid housed in the vessel, wherein the automatic analyzer comprises a calculation unit that calculates an amount of the liquid based on an electrostatic capacitance value measured by the electrostatic capacitance measuring mechanism when the probe contacts the liquid housed in the vessel.
The automatic analyzer according to claim 1, comprising a storage unit that stores a relationship between the electrostatic capacitance value and the amount of the liquid in advance, wherein the calculation unit calculates a liquid amount based on the relationship.
The automatic analyzer according to claim 2, wherein the relationship between the electrostatic capacitance value stored in the storage unit and the amount of the liquid varies depending on a shape of the vessel.
The automatic analyzer according to claim 1, wherein the calculation unit calculates the remaining amount of the liquid housed in the vessel based on a change in the electrostatic capacitance value measured by the electrostatic capacitance measuring mechanism at times of different aspirations when the probe contacts the liquid housed in the vessel.
The automatic analyzer according to claim 1, wherein the calculation unit calculates a transition of the remaining amount of the liquid housed in the vessel based on a change in the electrostatic capacitance value measured by the electrostatic capacitance measuring mechanism at times of different aspirations when the probe contacts the liquid housed in the vessel.
The automatic analyzer according to claim 1, comprising a detection unit detecting that the remaining amount of the liquid housed in the vessel is small based on a slope of a change in the electrostatic capacitance value measured by the electrostatic capacitance measuring mechanism when the probe contacts the liquid housed in the vessel at times of different aspirations.
The automatic analyzer according to claim 6, comprising an informing mechanism informing that the detection unit detects that the remaining amount of the liquid is small.
The automatic analyzer according to claim 5, comprising a display unit that displays a remaining amount calculated by the calculation unit.

Description

Technical Field This invention relates to an automatic analyzer. Background Art In an automatic analyzer used for clinical examination, for examination of a sample for a plurality of different analysis items, a dispensing probe is used to dispense the sample from a single sample vessel into a plurality of different reaction vessels corresponding to the number of analysis items. Many of used sample vessels have a test-tube shape with a vessel bottom of hemispherical shape. Because of this, when the remaining amount of the sample becomes not more than a certain amount after repeated aspirations of the sample, even if the sample remains, the sample will not be aspirated with the probe (the remaining amount of the sample at the time is referred to as dead volume). If a desired amount of the sample is not able to be aspirated, the analysis could result in failure because of no occurrence of normal reaction. To avoid the problem, it is helpful to aspirate the sample after the confirmation that the sample to be aspirated is still present in the sample vessel. Patent Literature 1 discloses an automatic analyzer that determines that a liquid is present in a sample vessel by using an electrostatic capacitance scheme to detect that the tip end of the probe contacts a liquid level in the vessel. Citation List Patent Literature Patent Literature 1: Japanese Unexamined Patent Application Publication No. Hei10(1998)-282116 Summary of Invention Technical Problem In the technology described in Patent Literature 1, by detecting a liquid level, the presence of a liquid in the vessel is detected. However, it is impossible to acquire directly how much the liquid remains in the vessel. In other words, the liquid level height is not able to be calculated from "the relationship between the liquid level height and the remaining amount of the sample" calculated based on a shape of the sample vessel. The acquisition of an accurate remaining amount of the sample is important especially when the remaining amount is close to dead volume. This is because, even though an analyzable sample remains, if a shortage of the remaining amount is determined, a precious sample will be wasted. On the other hand, even if it is determined that the remaining amount is sufficient, when the actually dispensed sample is insufficient, an analysis failure will occur and a reagent will be wasted. It is an object of the present invention to provide an automatic analyzer capable of avoiding the occurrence of analysis failures due to a shortage of the remaining amount of a liquid by directly acquiring the remaining amount of the liquid in a vessel. Solution to Problem To solve the above problem, the configuration of the present invention is as follows. An automatic analyzer includes: a probe that aspirates a liquid in a vessel; and an electrostatic capacitance measuring mechanism that measures electrostatic capacitance across the probe and the liquid housed in the vessel. The automatic analyzer includes a liquid amount calculation mechanism that calculates an amount of the liquid based on an electrostatic capacitance value measured by the electrostatic capacitance measuring mechanism when the probe contacts the liquid housed in the vessel. Advantageous Effects of Invention According to the present invention, an automatic analyzer is provided which is capable of avoiding the occurrence of analysis failures due to a shortage of the remaining amount of a liquid by directly acquiring the remaining amount of the liquid in a vessel. Brief Description of Drawings [FIG. 1] FIG. 1 is a plan view showing the overall configuration of an automatic analyzer.[FIG. 2] FIG. 2 is a schematic diagram of a dispensing probe and an electrostatic capacitance produced between the dispensing probe and an electrode opposite to the dispensing probe.[FIG. 3] FIG. 3 is a functional block diagram of the automatic analyzer.[FIG. 4] FIG. 4 shows a change in the electrostatic capacitance when the dispensing probe is lowered.[FIG. 5] FIG. 5 shows a relationship between the electrostatic capacitance mean value after contacting a liquid and the liquid amount when sample aspiration is repeated.[FIG. 6] FIG. 6 is a flowchart of determining the remaining amount of a sample from the electrostatic capacitance. Description of Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings. The following description presents specific examples of the subject matter of the invention, and the present invention is not limited to these descriptions. Thus, those skilled in the art can make various changes and modifications within the scope of the technical concept disclosed herein. In all of the drawings for describing the present invention, identical reference signs are used to indicate elements with identical functions, and repeated description thereof may be omitted in some cases. First Embodiment FIG. 1 shows an overview of an automatic analyzer 100. A