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Test ID: PMLR PML/RARA Quantitative, PCR, Varies

Reporting Name

PML/RARA Quantitative, PCR

Useful For

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

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

Specimen Type

Varies


Advisory Information


This 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.



Shipping Instructions


Refrigerated 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

2. Date of collection

3. Specimen source (blood or bone marrow)



Specimen Required


Submit only 1 of the following specimens:

 

Specimen Type: Whole blood

Container/Tube:

Preferred: EDTA (lavender top)

Acceptable: ACD (yellow top)

Specimen Volume: 10 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: 4 mL

Collection Instructions:

1. Invert several times to mix bone marrow.

2. Send specimen in original tube.

3. Label specimen as bone marrow.


Specimen Minimum Volume

Peripheral blood: 4 mL
Bone Marrow: 2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Refrigerated (preferred) 5 days PURPLE OR PINK TOP/EDTA
  Ambient  72 hours PURPLE OR PINK TOP/EDTA

Reference Values

An interpretive report will be provided.

 

If positive, a value representing a ratio of PML-RARA fusion transcript to the control gene ABL1 expressed as a percentage will be reported.

Day(s) and Time(s) Performed

Monday through Friday

Test Classification

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

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

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PMLR PML/RARA Quantitative, PCR In Process

 

Result ID Test Result Name Result LOINC Value
39469 PMLR Result No LOINC Needed
MP012 Specimen Type 31208-2
19449 Interpretation 69047-9

Clinical Information

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.

Interpretation

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 ABL1 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 (ABL1). 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.

Clinical Reference

1. 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

2. Adams J, Nassiri M: Acute Promyelocytic Leukemia A Review and Discussion of Variant Translocations. Arch Pathol Lab Med 2015;139:1308-1313

3. Kayser S, Schlenk RF, Platzbecker U: Management of patients with acute promyelocytic leukemia. Leukemia 2018;32:1277-1294

4. Ablain J, de The H: Revisiting the differentiation paradigm in acute promyelocytic leukemia. Blood 2011;117(22):5795-5802

Analytic Time

4 days

Method Name

Quantitative, Real-Time Polymerase Chain Reaction (PCR)

Forms

1. Hematopathology Patient Information (T676) in Special Instructions

2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.

Mayo Clinic Laboratories | Hematology Catalog Additional Information:

mml-acute-leukemia-myelodysplastic-syndromes