The National Comprehensive Cancer Network recommends testing for IDH gene mutations, to guide appropriate treatment of acute myeloid leukemia, or AML. In this test-specific episode of the "Answers From the Lab" podcast, Rong He, M.D., explains how Mayo Clinic Laboratories' IDHQ test improves upon next generation sequencing for assessing AML treatment options.

"IDHQ is a droplet digital PCR assay that offers the advantage of a much quicker turnaround time, which greatly facilitates timely therapeutic decisions," Dr. He says.

Having an IDH mutation can qualify patients for treatment with FDA-approved target therapies — or participation in potential clinical trials. The IDHQ assay is a quantitative analysis that evaluates for 16 hotspot mutations in genes IDH1 and IDH2, with an analytical sensitivity of 0.5%.

"This is a much nimbler test to help inform therapeutic decisions for newly diagnosed AML patients or AML patients presenting with relapse or refractory disease," Dr. He says.

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Testing

Useful information

IDHQ | IDH1 (R132) and IDH2 (R140 and R172) Quantitative Detection, Droplet Digital PCR, Varies

• Detecting IDH1 R132 and IDH2 R140 and R172 mutations in acute myeloid leukemia patients at the time of diagnosis to guide targeted therapy.
• Monitoring minimal residual disease during the clinical and therapeutic course.

FLT | FLT3 Mutation Analysis, Varies

• A prognostic indicator in some patients with acute myeloid leukemia.
• This test should not be used to monitor residual disease following treatment.

Specimen requirements

IDHQ | IDH1 (R132) and IDH2 (R140 and R172) Quantitative Detection, Droplet Digital PCR, Varies

The following information is required:

1. Pertinent clinical history.
2. Date of collection.
3. Specimen source (blood or bone marrow).

Submit only 1 of the following specimens

Specimen Type: Whole blood

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD-B) or green top (heparin)

Specimen Volume: 4mL

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 Stability: Refrigerated 14 days/ Ambient 7 days

Specimen Type: Bone marrow aspirate

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD-B) or green top (heparin)

Specimen Volume: 2mL

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 Stability: Refrigerated 14 days/ Ambient 7 days

Specimen Type: Extracted DNA from blood or bone marrow

Container/Tube: 1.5- to 2-mL tube with indication of volume and concentration of DNA

Specimen Volume: Entire specimen

Collection Instructions:

1. Label specimen as extracted DNA and source of specimen.
2. Indicate volume and concentration of DNA on label. The required volume of DNA is at least 50 mcL at a concentration of 50 ng/mcL.

Specimen Stability: Frozen (preferred)/Refrigerated

FLT | FLT3 Mutation Analysis, Varies

The following information is required:

1. Pertinent clinical history
2. Clinical or morphologic suspicion
3. Date and time of collection
4. Specimen source

Submit only 1 of the following specimens

Specimen Type: Peripheral blood

Container/Tube: Lavender top (EDTA) or yellow top (ACD)

Specimen Volume: 3 mL

Collections Instructions:

1. Invert several times to mix blood.
2. Send specimen in original tube. Do not aliquot.
3. Label specimen as blood.

Specimen Stability: Ambient (preferred)/Refrigerate

Specimen Type: Bone marrow

Container/Tube: Lavender top (EDTA) or yellow top (ACD)

Specimen Volume: 2 mL

Collections Instructions:

1. Invert several times to mix bone marrow.
2. Send specimens in original tube. Do not aliquot.
3. Label specimen as bone marrow.

Specimen Stability: Ambient (preferred)/Refrigerate

Specimen Type: Extracted DNA from blood or bone marrow

Container/Tube: 1.5- to 2-mL tube

Specimen Volume: Entire specimen

Collection Instructions:

1. 1. Label specimen as extracted DNA from blood or bone marrow.
2. 2. Indicate volume and concentration of DNA on the label.

Specimen Stability: Frozen (preferred)/Refrigerate/Ambient

Performance information

IDHQ | IDH1 (R132) and IDH2 (R140 and R172) Quantitative Detection, Droplet Digital PCR, Varies

Analytic time: 4 to 8 days

Days performed: Monday through Saturday

FLT | FLT3 Mutation Analysis, Varies

Analytic time: 3 to 6 days

Days performed: Monday through Saturday

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