Oxalate Analysis in Hemodialysate
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Determining of the amount of oxalate removed during a dialysis session
Individualizing the dialysis prescription of hyperoxaluric patients
Enzymatic Oxalate Oxidase
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Oxalate, Dialysate Fluid
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, 10-mL urine tube (Supply T068) or a clean, plastic aliquot container with no metal cap or glued insert
Specimen Volume: 5 mL
Collection Instructions: Adjust the pH of the specimen to 2.5 to 3.0 with 6N HCl.
1. Patient should avoid taking vitamin C supplements for 24 hours prior to dialysis.
2. Unacidified frozen hemodialysate delivered to the laboratory within 3 days from collection will be accepted and the following comment will be added to the result: In non-acidified hemodialysate stored frozen, oxalate values may increase spontaneously up to 30% (average 11% increase for dialysate oxalate stored for 48 hours, frozen, non-acidified).
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.
|Dialysate Fluid||Frozen||7 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Oxalate is a dicarboxylic acid, an end product of glyoxalate and glycerate metabolism that is excreted in the urine where it is a common component of kidney stones (up to 85%). Hyperoxaluria can be either genetic (eg, primary hyperoxaluria) or acquired/secondary (eg, enteric hyperoxaluria), and can lead to nephrocalcinosis and renal failure. Monitoring the adequacy of oxalate removal during hemodialysis can be useful in the management of patients with hyperoxaluria and renal failure, particularly following transplantation.
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.
A steady decrease in oxalate signal is expected through dialysis procedure.
Signals below 2 mcM should be considered ideal conditions.
Total oxalate removed during a dialysis session can be estimated by multiplying the concentration of oxalate in the dialysate by the oxalate flow rate for each time period that the oxalate is measured.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Proper specimen processing and acidification are essential to obtain a quality result and avoid nonenzymatic generation of oxalate from ascorbate.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Canavese C, Petrarulo M, Massarenti P, et al: Long-term, low-dose, intravenous vitamin C leads to plasma calcium oxalate supersaturation in hemodialysis patients. Am J Kidney Dis 2005 Mar;45(3):540-549
2. Koch GH, Strong FM. Determination of oxalate in urine. Anal Biochem 1969 Jan;27(1):162-171
3. Marangella M, Petrarulo M, Mandolfo S, et al: Plasma profiles and dialysis kinetics of oxalate in patients receiving hemodialysis. Nephron 1992;60(1):74-80
4. Marangella M, Vitale C, Petrarulo M, et al. Bony content of oxalate in patients with primary hyperoxaluria or oxalosis-unrelated renal failure. Kidney Int 1995;48(1):182-187
Method Description Describes how the test is performed and provides a method-specific reference
An enzymatic oxalate oxidase method for measuring oxalate in plasma and urine was adapted for dialysate fluid. The reaction yields hydrogen peroxide, which in the presence of peroxidase reacts with a dye to give a colored end point that is measured at 590 nm using a sensitive Beckman Coulter DU800 spectrophotometer.(Ladwig PM, Liedtke RR, Larson TS, Lieske JC: Sensitive spectrophotometric assay for plasma oxalate. Clin Chem 2005;51(12):2377-2380; Wilson DM, Liedtke RR: Modified enzyme-based colorimetric assay of urinary and plasma oxalate with improved sensitivity and no ascorbate interference: reference values and specimen handling procedures. Clin Chem 1991;37:1229-1235)
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 Friday; 10 a.m.
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.
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 modified from the manufacturer’s instructions. Its performance characteristics were determined 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|
|DOXA||Oxalate, Dialysate Fluid||47715-8|