PMLR/84114 Overview: PML/RARA Quantitative, PCR

Test Catalog

Test Name

Normal View

Test ID: PMLR
PML/RARA Quantitative, PCR

Useful For Suggests clinical disorders or settings where the test may be helpful

Diagnosis of acute promyelocytic leukemia (APL)

 

Detection of residual or recurrent APL

 

Monitoring the level of promyelocytic leukemia/retinoic acid receptor alpha (PML/RARA) in APL patients

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

See Acute Promyelocytic Leukemia: Guideline to Diagnosis and Follow-up in Special Instructions.

Special Instructions and Forms Library of PDFs including pertinent information and consent forms, specimen collection and preparation information, test algorithms, and other information pertinent to test

Method Name A short description of the method used to perform the test

Quantitative, Real-Time Polymerase Chain Reaction (PCR)

NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name

PML/RARA Quantitative, PCR

Aliases Lists additional common names for a test, as an aid in searching

(15;17)(q22;q12)
Acute myeloid leukemia (AML)
Acute promyelocytic leukemia (APL)
AML (acute myeloid leukemia)
AMPL
APL minimum residual disease
PCR
PML/RARA

Specimen Type Describes the specimen type validated for testing

Varies

Shipping Instructions

Refrigerate specimen must arrive within 5 days (120 hours of draw), and ambient specimens must arrive within 3 days (72 hours) of draw. Draw and package specimen as close to shipping time as possible.

Necessary Information

The following information is required:

1. Pertinent clinical history including if the patient has a diagnosis of chronic myelogenous leukemia or other bcr/abl-positive neoplasm

2. Date of collection

3. Specimen source (blood or bone marrow)

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.

Submit only 1 of the following specimens:

 

Specimen Type: Whole blood

Container/Tube:

Preferred: EDTA (lavender top)

Acceptable: ACD (yellow top)

Specimen Volume: 4 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

3. Label specimen as blood.

 

Specimen Type: Bone marrow

Container/Tube:

Preferred: EDTA (lavender top)

Acceptable: ACD (yellow top)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix bone marrow.

2. Send specimen in original tube.

3. Label specimen as bone marrow.

Forms

1. Hematopathology Patient Information (T676) in Special Instructions

2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request Form (T726) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/hematopathology-request-form.pdf)

Specimen Minimum Volume The amount of sample necessary to provide a clinically relevant result as determined by the Laboratory.

1 mL

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected

Hemolysis

Mild OK; Gross reject

Lipemia

NA

Icterus

NA

Other

Moderately to severely clotted

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperatures are also included.

Specimen TypeTemperatureTime
VariesRefrigerated (preferred)5 days
 Ambient 72 hours

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Acute promyelocytic leukemia (APL) accounts for 5% to 10% of acute myeloid leukemia, and generally has a good prognosis with current treatment protocols. APL cells contain a fusion gene comprised of the downstream sequences of the retinoic acid receptor alpha gene (RARA) fused to the promoter region and upstream sequences of one of several genes, the most common (>80%) being the promyelocytic leukemia gene (PML). The fusion gene is designated PML/RARA and may be seen in a karyotype as t(15;17)(q22;q12). Messenger RNA (PML/RARA) produced from the fusion gene can be detected using a PCR-based assay, and indicates the presence of neoplastic cells. The PCR-based assay has greater sensitivity than standard methods such as morphology review, karyotyping, or FISH.

 

Recent studies have indicated that sensitive monitoring is important because the majority of patients who remain PCR positive, or become PCR positive again following treatment, will relapse and likely benefit from early intervention for residual/recurrent disease. This quantitative assay allows PML/RARA levels to be monitored rather than simply detecting the presence or absence of disease.

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.

An interpretive report will be provided.

 

If positive, a value representing a ratio of PML-RARA fusion transcript to the control gene GusB expressed as a percentage will be reported.

Interpretation Provides information to assist in interpretation of the test results

The assay is reported in the form of a normalized ratio of promyelocytic leukemia/retinoic acid receptor alpha (PML-RARA) fusion transcript to the control gene GusB expressed as a percentage, which is an estimate of the level of PML/RARA RNA present in the specimen, expressed in relation to the level of RNA from an internal control gene (beta glucuronidase, designated GUSB). The normalized ratio has no units but is directly related to the level of PML/RARA detected (ie, larger numbers indicate higher levels of PML/RARA and smaller numbers indicate lower levels). A relative expression value minimizes variability in the RNA levels measured in separate specimens tested at different times. Although a quantitative PCR assay is performed, the precision of the assay is such that results must be considered semiquantitative, and it is recommended that only log changes be considered significant. Critical results, such as a change in the status of positivity, should be repeated on a separate specimen to verify the result.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Promyelocytic leukemia/retinoic acid receptor alpha (PML/RARA) levels can only be compared reliably if tested in the same laboratory using the same procedure each time.

 

The assay will only detect PML/RARA RNA and will not detect RNA from the less common RARA fusion genes.

 

The assay may not detect rare, unusual PML/RARA fusions. Therefore, if the assay is going to be used for monitoring after treatment, the test should be performed at the time of diagnosis to ensure that the test gives a positive result.

Clinical Reference Recommendations for in-depth reading of a clinical nature

Grimwade D, Lo Coco F: Acute promyelocytic leukemia: a model for the role of molecular diagnosis and residual disease monitoring in directing treatment approach in acute myeloid leukemia. Leukemia 2002 October;16(10):1959-1973

Method Description Describes how the test is performed and provides a method-specific reference

Total RNA is extracted from blood or bone marrow using the QIAmp kit (Qiagen). cDNA is made using the Superscript III kit (Invitrogen). Quantitative, real-time PCR is performed using the LightCycler instrument (Roche) and the data analyzed using the supplied software for relative quantification with calibrator normalization and efficiency correction.(Instruction manual: Roche Applied Science LightCycler 2.0 Instrument. Version 4/1.2. 2003. Roche Diagnostics)

 

The normalized ratio is a relative quantification calculation as follows: 

Normalized ratio*=

PML/RARA (sample)

GUSB (sample)

PML/RARA (calibrator)

GUSB (calibrator)

 

*Where GUSB mRNA is used to normalize variations in RNA quality and calibrator mRNA from a promyelocytic leukemia/retinoic acid receptor alpha (PML/RARA)-positive cell line is used to normalize variations in run conditions.

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information

No

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

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.

4 days

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result

8 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

RNA stored 3 months

Performing Laboratory Location The location of the laboratory that performs the test

Rochester

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 manufacturers 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.

CPT codes are provided by the performing laboratory.

81315-PML/RARalpha (t(15;17)), (PML-RARA regulated adaptor molecule 1) (eg promyelocytic leukemia) translocation analysis; common breakpoints (eg, intron 3 and intron 6), qualitative or quantitative

LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and result codes of this test.

LOINC codes are provided by the performing laboratory.

Test IDTest Order NameOrder LOINC Value
PMLRPML/RARA Quantitative, PCRIn Process

 

Result IDTest Result NameResult LOINC Value
39469PMLR ResultIn Process
MP012Specimen Type31208-2
19449Final Diagnosis34574-4