Inherited Conjugated Hyperbilirubinemias, Urine
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Differential diagnosis of hyperbilirubinemia syndromes between Dubin-Johnson syndrome and Rotor syndrome in patients > or =1 year of age
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
Investigation of inherited conjugated hyperbilirubinemia syndromes (Dubin-Johnson syndrome, Rotor syndrome) only.
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
High-Performance Liquid Chromatography (HPLC)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Inher Conj Hyperbilirubinemias, U
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: Amber, 60-mL urine bottle (Supply T596)
Specimen Volume: 20-50 mL
1. Patient should abstain from alcohol for at least 24 hours before as well as during the collection period.
2. Collect urine for 24 hours.
3. Add 5 g of sodium carbonate as preservative at start of collection. This preservative is intended to achieve a pH of >7. Do not substitute sodium bicarbonate for sodium carbonate.
4. The container should be refrigerated and protected from light as much as possible during collection.
5. Protect specimen from light.
1. 24-Hour volume is required.
2. Include a list of medications the patient is currently taking.
3. The pH will generally fall between 7 and 10 if the proper preservative (5 g sodium carbonate) was added to the container before the collection was started.
4. 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 not light protected
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Dubin-Johnson syndrome (DJS) and Rotor syndrome are 2 of the inherited disorders of bilirubin metabolism which result in conjugated hyperbilirubinemia. DJS is inherited as an autosomal recessive trait that is rarely detected before puberty. It is characterized by chronic, nonhemolytic jaundice. Most patients are asymptomatic and the liver typically shows abnormal black pigmentation. The gene responsible for this disorder is a member of the family of ATP-binding cassette transporters located on chromosome 10q24, called MRP2 or cMOAT. This defect impairs liver excretion of conjugated bilirubin and several organic anions from the hepatocytes into the bile. Other liver function tests are normal.
Rotor syndrome is a rare condition of the liver and very similar to DJS. It is inherited as an autosomal recessive trait caused by digenic inheritance of homozygous mutations in the SLCO1B1 and SLCO1B3 genes. Biochemically, Rotor syndrome can be distinguished from DJS by a normal functioning gallbladder, normal liver histology, and the different pattern of coproporphyrin isomers excretion.
In healthy individuals, the percent of coproporphyrin I excreted relative to the total coproporphyrin excreted in urine is approximately 20% to 45%. In DJS and Rotor syndrome, retention of coproporphyrin III by the liver causes diminished urinary excretion. Consequently the percent of coproporphyrin I to the total coproporphyrin excreted in the urine exceeds the normal range.
When the total urinary excretion of coproporphyrin is elevated and the percent of coproporphyrin I to total coproporphyrin exceeds 60% but is <80%, is most consistent with Rotor syndrome. In patients with DJS the percentage of coproporphyrin I to total coproporphyrin is typically >80% and the total urinary coproporphyrin excretion is within normal limits. Some overlap may exist so the ratio alone should not be used to distinguish Rotor or DJS.
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.
COPROPORPHYRIN ISOMERS I AND III
25-150 mcg/24 hours
8-110 mcg/24 hours
% COPROPORPHYRIN I
Abnormal results are reported with a detailed interpretation including an overview of the results and their significance, a correlation to available clinical information provided with the specimen, differential diagnosis, and recommendations for additional testing when indicated and available, and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test is not useful for the evaluation of individuals <1 year of age suspected of having Dubin-Johnson syndrome or Rotor syndrome. Due to normal liver development, coproporphyrin I is primarily excreted in infant urine and cannot be interpreted in the scope of hyperbilirubinemia syndromes.
This test is not useful for evaluating patients with suspected porphyrias. For measurement of urine coproporphyrin and uroporphyrin, see PQNU/8562Porphyrins, Quantitative, Urine or PQNRU/60597 Porphyrins, Quantitative, Random, Urine.
Failure to maintain low temperature and correct pH may allow analyte degradation and result in falsely-decreased coproporphyrin III values (ie, false positives).
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Koskelo P, Mustajoki P: Altered coproporphyrin-isomer excretion in patients with the Dubin-Johnson syndrome. Int J Biochem 1980;12:975-978
2. Chowdhury JR, Wolkoff AW, Chowdhury NR, et al: Hereditary jaundice and disorders of bilirubin metabolism. In Metabolic and Molecular Basis of Inherited Disease, Eighth edition. Edited by CR Scriver, AL Beaudet, WS Sly, et al. New York, McGraw-Hill Medical Publishing Division, 2001, pp 3063-3101, Available from URL: www.ommbid.com
Method Description Describes how the test is performed and provides a method-specific reference
After the urine specimen is acidified, the isomers are separated by HPLC.(Lim CK, Peters TJ: High-performance liquid chromatography of uroporphyrin and coproporphyrin isomers. Methods Enzymol 1986;123:383-389)
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.
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.
3 days (not reported on Saturday or Sunday)
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 was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
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|
|8652||Copro I + III||In Process|
|2394||% Copro I||In Process|
|TM74||Collection Duration||In Process|
|VL57||Urine Volume||In Process|