Molybdenum/Creatinine Ratio, Urine
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Monitoring of parenteral nutrition
Monitoring metallic prosthetic implant wear
As an indicator of molybdenum cofactor disease
Profile Information A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
|Test ID||Reporting Name||Available Separately||Always Performed|
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
MOLYC/29344: Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)
CDCR/7243: Enzymatic Colorimetric Assay
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
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.
Collection Container/Tube: Clean, plastic urine collection container
Submission Container/Tube: Plastic, 6-mL tube (Supply T465) or a clean, plastic aliquot container with no metal cap or glued insert
Specimen Volume: 6 mL
1. Collect a random urine specimen.
2. Shake the specimen gently.
3. See Metals Analysis-Collection and Transport in Special Instructions for complete instructions.
Additional Information: High concentrations of gadolinium and iodine are known to interfere with most metals tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.
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)||28 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Molybdenum is an essential trace element found in the daily diet. It is a cofactor for some enzymes important in nitrogen metabolism (aldehyde dehydrogenase, xanthine oxidase, NADH dehydrogenase). Due to the wide distribution of molybdenum in the environment and particularly in plant materials, molybdenum deficiency is rare in adults with normal, diverse diets. Typical molybdenum intake in most geographic locations is between 45 and 90 mcg/day.(1) Urine is the primary source of excretion, though excesses are sometimes excreted by the biliary route.(2-3)
Molybdenum deficiency associated with parenteral nutrition is indicated by symptoms such as stunted growth, reduced appetite, tachycardia, tachypnea, blindness and coma. These symptoms can be corrected by introducing molybdenum supplementation.(3) Molybdenum cofactor disease is a severe genetic disorder that is due to defective mutations in the MOCS1, MOCS2, and GEPH genes.(4)
Molybdenum toxicity is rare and usually related to molybdenum mining exposure; however, it has been observed in cases of intake >400 mcg/day. Molybdenum interferes with copper uptake; molybdenum toxicity is predominantly due to copper deficiency (hypochromic anemia and neutropenia) and inhibition of xanthine oxidase (uric acid accumulation).
Urine molybdenum concentrations are likely to be increased above the reference range in patients with metallic joint prosthesis. Prosthetic devices produced by Zimmer Company and Johnson and Johnson typically are made of aluminum, vanadium, and titanium. Prosthetic devices produced by Depuy Company, Dow Corning, Howmedica, LCS, PCA, Osteonics, Richards Company, Tricon, and Whiteside typically are made of chromium, cobalt, and molybdenum. This List of products is incomplete, and these products change occasionally; see prothesis product information for each device for composition details.(4-5)
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.
6-11 years: 70-240 mcg/g creatinine
>11 years: 40-100 mcg/g creatinine
Reference values have not been established for patients that are <6 years of age.
Molybdenum excretion rates are variable and related to dietary intake. Evaluation of 124 healthy adults by Mayo Clinic suggested a reference range of 6 to 190 mcg/L. The National Health and Nutrition Examination Survey (NHANES) study reported urine molybdenum ranged from 20 to 180 mcg/L. (Note: NHANES also reported excretion per gram of creatinine as 40-100 mcg/gm creatinine in adults and 70-240 mcg/gm creatinine in children.)
Prosthesis wear is known to result in increased circulating concentration of metal ions.(5-7) No increase (6-190 mcg/L) in urine molybdenum concentration is evident with a prosthetic device in good condition. Urine concentrations >200 mcg/L in a patient with molybdenum-based implant suggest significant prosthesis wear. Increased urine trace element concentrations in the absence of corroborating clinical information do not independently predict prosthesis wear or failure.
Urine molybdenum <6 mcg/L indicates potential deficiency.
Increased urine molybdenum may be seen in acute viral hepatitis, chronic active hepatitis, alcoholic liver disease, and other forms of liver inflammation.(2)
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Molybdenum is a trace metal commonly used in alloys and readily present in the environment. Thus, contamination of the specimen must be avoided. Failure to use metal-free collection procedures and devices may cause falsely increased results. See Specimen Required for collection and processing information.
High concentrations of gadolinium and iodine are known to interfere with most metals tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Third National Report on Exposure to Environmental Chemicals (NHANES). NCEH Publication 05-0570. Department of Human Service, Centers for Disease Control and Prevention. July 2005
2. Tsalev DL, Zaprianov ZK: Atomic Absorption Spectrometry in Health Practice, CRC Press, 1984
3. Shenkin A, Baines M, Fell GS, Lyon TDG: Vitamins and trace elements. In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Edited by CA Burtis, ER Ashwood, DE Bruns. St. Louis, Elsevier Saunders, 2006, p 1132
4. Reiss J, Johnson J: Mutations in the molybdenum cofactor biosynthetic genes MOCS1, MOCS2, and GEPH. Hum Mutat 2003;21:569-576
5. Liu TK, Liu SH, Chang CH, Yang RS: Concentration of metal elements in the blood and urine in the patients with cementless total knee arthroplasty. Tohoku J Exp Med 1998;185:253-262
6. Lhotka C, Szekes T, Stefan I, et al: Four-year study of cobalt and chromium blood levels in patients managed with two different metal-on-metal total hip replacements. J Orthop Res 2003;21:189-195
Method Description Describes how the test is performed and provides a method-specific reference
Molybdenum in urine is analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). Aqueous acidic calibrating standards, reagent blanks, quality control specimens, and patient sample digests are diluted with aqueous acidic diluent containing internal standards. These diluted samples are aspirated by a pneumatic high-pressure nebulizer driven by argon gas and directed into a high-temperature (6800 K) argon gas discharge (plasma). This discharge decomposes, atomizes, and ionizes the nebulized particles. All atoms, molecules, and ions formed in the discharge are extracted into a mass spectrometer through a platinum orifice. Molybdenum ions are separated from the concomitants by the quadrupole-mass spectrometer. Instrument detector signals from the molybdenum ions are directly proportional to the concentration in the sample.(Unpublished Mayo method)
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.
Thursday; 11 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
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|
|89474||Molybdenum/Creat, U||In Process|