Test Overview
Test Methodology

i-Stat - ion-selective electrode potentiometry (Na, K), amperometry (creatinine),conductometry (hematocrit)

Test Usage

Performed at authorized locations by point of care operators

Sodium- monitoring electrolyte imbalances.

Potassium- monitoring and aiding in the diagnosis of diseases and clinical conditions that manifest high and low potassium levels.

Creatinine- used in the diagnosis and treatment of renal diseases, in monitoring renal dialysis, and as a calculation basis for measure other urine analytes.

Hematocrit- aid in the determination and monitoring of normal or abnormal total red cell volume status that can be associated with conditions including anemia and erythrocytosis.

Reference Range *

Analyte reference ranges are available in the i-Stat test procedure located on the POC website: https://www.pathology.med.umich.edu/point-of-care.

Test Limitations

•Specimens must be free of clots and fibrin strands.
•Prolonged tourniquet application (venous stasis) and forearm exercise may decrease pH due to localized production of lactic acid. This in turn can affect ionized calcium.
•Results may be affected in the following situations: hemolysis, traumatic draw, pumping fist during draw, extended delay between drawing and testing specimen, exposure to air, and obtaining specimen from an arm with an IV.
•Results outside the reportable ranges for the system will be display with a "<" or ">" symbol.

Test Details
Analytic Time

2 minutes

Soft Order Code
MiChart Code
POC I-Stat Lytes, Creatinine, HCT
Point of Care
Point of Care
Specimen Requirements
Collection Instructions

Collect in lithium heparin syringe/tube.

Special Handling

Samples must be tested within 30 minutes of collection and immediately after exposing the sample to room air.

Normal Volume
3 mL whole blood
Minimum Volume
65 µL whole blood
Rejection Criteria
Specimens; containing clots, collected in anticoagulant other than lithium or sodium heparin, older than 30 minutes.
Additional Information

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

CPT Code
Sodium (84295QW), Potassium (84132QW), Creatinine (82565QW), Hematocrit (85014QW)
Sodium(39791-9), Potassium (39789-3), Creatinine (38483-4), Hematocrit (41654-5)
NY State Approved