NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Urine K+ is useful in determining the cause for hyper- or hypokalemia.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Potentiometric, Indirect Ion-Selective Electrode
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
K (Potassium) Urine
K (Potassium) Urine
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube: Plastic, 6-mL tube (Supply T465)
Specimen Volume: 5 mL
1. Collect urine for 24 hours.
2. Add 25 mL of 50% acetic acid as preservative at start of collection.
1. 24-Hour volume is required.
2. Specimen collected with toluene urine collected with no preservative if kept refrigerated continuously is acceptable.
3. See Urine Preservatives in Special Instructions for multiple collections.
Urine Preservative Collection Options
50% Acetic Acid
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Urine||Refrigerated (preferred)||7 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Potassium (K+) is the major intracellular cation. Functions of
potassium include regulation of neuromuscular excitability, heart
contractility, intracellular fluid volume, and hydrogen ion concentration.
The physiologic function of K+ requires that the body maintain a low
extracellular fluid (ECF) concentration of the cation; the intracellular
is 20 times greater than the extracellular K+concentration. Only 2% of
total body K+ circulates in the plasma.
The kidneys provide the most important regulation of K+. The proximal
tubules reabsorb almost all the filtered K+. Under the influence of
aldosterone, the remaining K+ can then be secreted into the urine in
exchange for sodium in both the collecting ducts and the distal tubules.
Thus, the distal nephron is the principal determinant of urinary K+ excretion.
Decreased excretion of K+ in acute renal disease and end-stage
renal failure are common causes of prolonged hyperkalemia.
Renal losses of K+ may occur during the diuretic (recovery) phase
of acute tubular necrosis, during administration of non-potassium
sparing diuretic therapy, and during states of excess mineralo-
corticoid or glucocorticoid.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
17-77 mmol/24 hours
Hypokalemia reflecting true total body deficits of K+ can be classified
into renal and nonrenal losses based on the daily excretion of K+
in the urine. During hypokalemia, if urine excretion of K+ is <30 mEq/d,
it can be concluded that renal reabsorption of K+ is appropriate.
In this situation, the causes for the hypokalemic state are either
decreased K+ intake or extra renal loss of K+ rich fluid. Urine
excretion of >30 mEq/d in a hypokalemia setting is inappropriate
and indicates that the kidneys are the primary source of the lost
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Ion selective electrodes are selective for the ion in question but
are not absolutely specific. Other monovalent cations may interfere
but not in the physiologic range.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Tietz Textbook of Clinical Chemistry. 3rd edition. Edited by CA
Burtis, ER Ashwood. Philadelphia, WB Saunders Co, 2001
2. Toffaletti J: Electrolytes. In Professional Practice in Clinical
Chemistry: A Review. Edited by DR Dufour, N Rifai. Washington,
AACC Press, 1993
Method Description Describes how the test is performed and provides a method-specific reference
Ion selective electrode using indirect potentiometry.
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Sunday Varies
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Same day/1 day
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|KURU||Potassium, 24 Hr, U||51720-1|