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IVD DEVICE CALIBRATION IS MOST COMMONLY PERFORMED USING CALIBRATORS (REFERENCE MATERIALS) SPECIFICALLY INTENDED TO BE USED AS A STANDARD CURVE OR CUT-OFF POINT FOR AN ASSAY. A CALIBRATOR HAS AN ASSIGNED VALUE THAT IS ESTABLISHED BY THE MANUFACTURER BY A REFERENCE METHOD. CALIBRATORS EXIST IN A VARIETY OF MATRICES SUCH AS SIMULATED AQUEOUS, SERUM. PLASMA OR OTHER TYPES OF SPECIMENS. PRIMARY REFERENCE CALIBRATORS ARE HIGHLY PURIFIED CHEMICALS THAT CAN BE DIRECTLY WEIGHED OR MEASURED TO PRODUCE A SOLUTION OF KNOWN CONCENTRATION. ALTERNATIVELY, THEY MAY BE MORE COMPLEX BIOLOGICAL MATERIALS HAVING RECEIVED A VALUE ASSIGNMENT USING REFERENCE (STANDARD) METHODOLOGY. THEY ARE SUPPLIED WITH A CERTIFICATE OF ANALYSIS FOR EACH LOT (FOR EXAMPLE, STANDARD REFERENCE MATERIALS (SRMS) FROM THE U.S. NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY (NIST)). THE PRIMARY CALIBRATOR "CALIBRATION SOLUTION FOR OSMOMAT 010 / 030 / auto" IS USED TO CALIBRATE THE OSMOMETERS "OSMOMAT 030" AND "OSMOMAT AUTO", WHICH BOTH ARE FREEZING-POINT OSMOMETERS FOR USE IN CLINICAL CHEMISTRY. THE OSMOLALITY OF THE CALIBRATOR IS EQUAL TO THE OSMOLALITY OF BODY-FLUIDS (ISOTONIC SOLUTION), PROVIDING THAT THE OSMOMETER WILL BE CALIBRATED CORRECTLY FOR THE FLUIDS TO BE MEASURED FOR MEDICAL PURPOSES.

A FREEZING-POINT OR CRYOSCOPIC OSMOMETER IS A DEVICE TO MEASURE THE NUMBER OF MOLECULES OR IONS DISSOLVED IN A FLUID, IN THIS CASE, WATER. THE PHYSICAL EFFECT THE MEASUREMENT IS BASED ON IS THAT DISSOLVED SUBSTANCES IN WATER DEPRESS THE FREEZING POINT OF THE SOLUTION. THIS DEPRESSION IN THE FREEZING TEMPERATURE ITSELF, MEASURED EXACTLY, GIVES AN EXACT MEASURE FOR HOW MANY MOLECULES OR IONS ARE DISSOLVED IN THE AQUEQUS CALIBRATOR OR SPECIMEN. THIS EFFECT IS PHYSICAL, WHICH MEANS THAT THE CHEMICAL PROPERTIES OF THE CALIBRATOR OR SPECIMEN REMAIN UNCHANGED. AS ANY DISSOLVABLE SUBSTANCE CAUSES THIS EFFECT, THE RESULT OF THE MEASUREMENT GIVES NO INFORMATION ABOUT THE IDENTITY AND/OR COMPOSITION OF THE SUBSTANCES DISSOLVED, IF THERE SHOULD BE SEVERAL. THE MEASURED VALUE EXPRESSES IF THE RANGE OF OSMOLALITY OF THE SPECIMEN IS TO BE EXPECTED AS BEING NORMAL FOR A SPECIMEN FROM A HEALTHY HUMAN BEING. OR THE OSMOLALITY SHOWS THAT SOMETHING IS WRONG WITH THE PATIENT. FURTHER MEDICAL EXAMINATIONS WOULD FOLLOW. IN THE CALIBRATOR THE ONLY SUBSTANCE DISSOLVED IS SODIUM CHLORIDE. SO THE VALUE OF THE OSMOLALITY ALSO REPRESENTS THE CONCENTRATION OF SODIUM CHLORIDE. TO MEASURE THE FREEZING-POINT-DEPRESSION. THE SAMPLE IS FROZEN CAREFULLY. THE EXACT TEMPERATURE OF THE FLUID IS MEASURED AT ANY TIME WHILE THE SAMPLE IS COOLED DOWN. THE TEMPERATURE AT WHICH THE FLUID FREEZES TO ICE IS DETERMINED EXACTLY AND THE INTERNAL CALCULATOR OF THE OSMOMETER CALCULATES AND DISPLAYS THE EQUIVALENT OSMOLALITY OF THE LIQUID. IN MATRICES LIKE URINE THE MEASUREMENT SHOWS IF THE KIDNEYS WORK PROPERLY ASSUMABLY.