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Test Code 291 Osmolality, Serum

Additional Codes


PowerChart: Osmolality Serum

MA Cerner: Osmolality Level

Specimen Requirement

0.5 mL serum is required. Serum gel tubes are acceptable.
Specimen integrity: icterus, lipemia, and hemolysis are acceptable with serum samples.

Additional Specimen Collection Information

Collect blood in a red-top tube.

Serum and urine specimens should be tested as soon as possible after collection in order to obtain accurate osmolality results. It is recommended that specimens are tested within 24 hours. Specimens can be refrigerated at 2-8 °C for up to 7 days.

Useful For

Evaluating acutely ill or comatose patients.


Testing is performed Monday through Sunday.

Typically completed within 4 hours after the specimen arrives at the testing site.

CPT Code Information

83930 Chemistry: Osmolality; blood

LOINC Code Information

2692-2 Osmolality Of Serum Or Plasma

Test Method

Freezing Point Osmometry; Osmo 1, Advanced Instruments

Reference Values

275-295 mOsm/kg

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