Advanced Instruments Osmometer -freezing-point depression
Performed at authorized locations by point of care operators. Serum and Urine osmolality are included.
Hyper osmolality in serum is most often associated with diabetes mellitus, and uremia. Abnormally low ratios occur in disease states such as; lymphomas, cancer, liver failure, shock, acute infections, and myocardial infarctions. In special cases of acute toxicity due to overdose of drugs, findings of normal serum sodium and high serum osmolality may be considered as an indication for dialysis. In dehydration, where water loss exceeds salt loss, the osmolality and the serum sodium increase, but the ratio stays normal. Examples are prolonged diarrhea and peritonitis or intestinal obstruction in which fluid has been sequestered outside the vascular system.
Reference ranges are available in the Osmolality test procedure located on the POC website: https://www.pathology.med.umich.edu/point-of-care.
No significant interference due to hemolysis, icterus, or lipemia. A comment should be entered with the results if grossly hemolyzed specimens are tested.
Collect blood in SST or sodium, lithium heparin for serum osmolality measurement. Collect urine in plastic urine cup.
Serum (SST or red top tubes) must be spun at 4000 rpm for 12 minutes before being processed.
For more test specific information, please refer to the test procedure found on the Michigan Medicine POC website: https://www.pathology.med.umich.edu/point-of-care