| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Osmolality, Plasma or Serum
Test CodeOSMO - NOCO
CPT Codes
83930
Preferred Specimen
1 mL plasma from Green top (Lithium Heparin).
Minimum Volume
0.5 mL
Other Acceptable Specimens
1 mL serum from Serum Gel or Red Top
Specimen Stability
| Specimen Type | Temperature | Time |
| Plasma Li Hep | Refrigerated | 3 days |
| Serum SST | Refrigerated | 3 days |
| Red Top – Separated* | Refrigerated | 3 days |
*Centrifuge and aliquot into a plastic vial.
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis
Methodology
Freezing Point Depression
Setup Schedule
Monday through Sunday; Continuously
Report Available
Same day
Reference Range
NCMC & BFCMC
280-290 mosm/kg
MMC
0 - 1 month: 266 - 295 mosm/kg
1 month - 61 years: 275 - 295 mosm/kg
61 - 150 years: 280 - 301 mosm/kg
280-290 mosm/kg
MMC
0 - 1 month: 266 - 295 mosm/kg
1 month - 61 years: 275 - 295 mosm/kg
61 - 150 years: 280 - 301 mosm/kg
Clinical Significance
Osmolality is used to evaluate the concentrating ability of the tubules in the kidneys.
Low serum or plasma osmolality levels are seen in adrenocortical insufficiency, panhypopituitarism, water intoxication and
postoperative status, (especially with excessive water replacement therapy, syndrome of inappropriate ADH secretion).
High serum or plasma osmolality levels are seen with water depletion, hyper-osmolar, nonketotic diabetic coma, diabetic
ketoacidosis, hypernatremic ethanol intoxication, diabetes insipidus, hypercalcemia, cerebral lesions, and often with tube feeding.
Low urine osmolality levels are seen with diabetes insipidus and primary polydipsia. After fluid restriction of 12-14 hours, a patient
with normal renal function should be able to concentrate urine to at least 800 mOsm/kg. Loss of this function is seen in early renal
failure, and a concentration ability of only 400 mOsm/kg would indicate severe renal dysfunction.
Low serum or plasma osmolality levels are seen in adrenocortical insufficiency, panhypopituitarism, water intoxication and
postoperative status, (especially with excessive water replacement therapy, syndrome of inappropriate ADH secretion).
High serum or plasma osmolality levels are seen with water depletion, hyper-osmolar, nonketotic diabetic coma, diabetic
ketoacidosis, hypernatremic ethanol intoxication, diabetes insipidus, hypercalcemia, cerebral lesions, and often with tube feeding.
Low urine osmolality levels are seen with diabetes insipidus and primary polydipsia. After fluid restriction of 12-14 hours, a patient
with normal renal function should be able to concentrate urine to at least 800 mOsm/kg. Loss of this function is seen in early renal
failure, and a concentration ability of only 400 mOsm/kg would indicate severe renal dysfunction.
Performing Laboratory
Banner Fort Collins Medical Center Laboratory
Mckee Medical Center Laboratory
North Colorado Medical Center Laboratory
