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Test Code LAB2265 PML::RARA Quantitative, PCR, Varies

Additional Codes

PMLR

Useful For

Diagnosis of acute promyelocytic leukemia (APL)

 

Detection of residual or recurrent APL

 

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

Testing Algorithm

For more information see Acute Promyelocytic Leukemia: Guideline to Diagnosis and Follow-up

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Varies


Ordering Guidance


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


1. Refrigerated specimens must arrive within 5 days of collection, and ambient specimens must arrive within 3 days of collection.

2. Collect 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: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 10 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

3. Label specimen as blood.

 

Specimen Type: Bone marrow

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 4 mL

Collection Instructions:

1. Invert several times to mix bone marrow.

2. Send bone marrow specimen in original tube. Do not aliquot

3. Label specimen as bone marrow.


Specimen Minimum Volume

Blood: 8 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
Medical University of South Carolina Note:

On-campus collections: Tube to 99 or deliver to University Extension Hospital Room EH318 
Send specimen Refrigerated
 
Off-campus collections: DO NOT SPIN! Specimen to be stored/transported at Refrigerated temp. 

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) Performed

Monday through Saturday

CPT Code Information

81315-PML/RAR-alpha (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

Interpretation

The assay is reported in the form of a normalized ratio of PML::RARA (promyelocytic leukemia/retinoic acid receptor alpha) 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 polymerase chain reaction 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.

Method Description

Total RNA is extracted from blood or bone marrow and reverse transcribed to generate complementary DNA. Quantitative real-time polymerase chain reaction is performed using the LightCycler instrument platform (Roche) and the data analyzed using the dedicated software for relative quantification with calibrator normalization. Results are provided as a normalized relative value of PML::RARA/ABL1 messenger RNA (mRNA) with a reproducible analytical sensitivity of 0.003%(Unpublished Mayo method).

 

The normalized ratio is a relative quantification calculation as follows: 

Normalized ratio*=

PML::RARA (sample)

ABL1 (sample)

PML::RARA (calibrator)

ABL1 (calibrator)

 

*Where ABL1 mRNA is used to normalize variations in RNA quality and calibrator mRNA from a PML::RARA-positive cell line is used to normalize variations in run conditions.

Report Available

4 to 8 days

Specimen Retention Time

Blood/Bone marrow: 2 weeks; Extracted RNA: 3 months

Reject Due To

Gross hemolysis Reject
Moderately to severely clotted Reject

Method Name

Quantitative, Real-Time Polymerase Chain Reaction (PCR)

Secondary ID

84114

Forms

1. Hematopathology Patient Information (T676)

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