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100+ Free MDT Practice Questions

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Which collection tube is preferred for whole-blood specimens used in HIV viral load and other molecular infectious disease assays?

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B
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Key Facts: MDT Exam

200

Total Items

AMT MDT

3 hrs

Exam Time

AMT

$210

Application Fee

AMT

1 yr

Molecular Experience

Or approved program

AMT MDT is the molecular diagnostics technologist credential. 200 items, 3 hours, $210. Master PCR thermal profile (denat 94-95°C / anneal 50-65°C / extend 72°C), qPCR Ct interpretation, Sanger ddNTP chain termination, NGS workflow, FISH for HER2/BCR-ABL, CPIC pharmacogenomics (CYP2D6 codeine, HLA-B*5701 abacavir), and SARS-CoV-2 RT-PCR targets.

Sample MDT Practice Questions

Try these sample questions to test your MDT exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which biosafety level (BSL) is appropriate for routine clinical molecular diagnostic work involving extracted nucleic acids from low-risk specimens?
A.BSL-1
B.BSL-2
C.BSL-3
D.BSL-4
Explanation: BSL-2 practices and facilities are standard for clinical molecular diagnostic laboratories handling human specimens that may contain bloodborne pathogens (HIV, HBV, HCV) and most clinically relevant infectious agents. BSL-2 requires a BSC for aerosol-generating procedures, sharps precautions, and standard PPE.
2What is the PRIMARY purpose of physically separating pre-PCR and post-PCR work areas in a molecular diagnostics laboratory?
A.To comply with OSHA noise regulations
B.To prevent amplicon contamination of new reactions
C.To allow simultaneous testing of more samples
D.To reduce reagent costs
Explanation: Pre- and post-PCR areas are separated to prevent amplified DNA (amplicons) from contaminating new reactions, which would cause false positives. Each cycle of PCR generates billions of copies; even minute carryover can contaminate downstream tests. Separate rooms, dedicated equipment, unidirectional workflow, and PPE all reduce this risk.
3A technologist notices unexpected amplification in a no-template control (NTC). What is the MOST likely cause?
A.Insufficient annealing temperature
B.Reagent or workspace contamination with template or amplicons
C.Expired Taq polymerase
D.Power surge during cycling
Explanation: An NTC with amplification almost always indicates contamination of reagents, pipettes, or the workspace with template DNA or carryover amplicons. The lab should stop testing, decontaminate (10% bleach, UV), discard suspect reagents, and re-run controls before resuming patient testing.
4Which decontaminant is MOST effective for destroying residual DNA on bench surfaces in a molecular laboratory?
A.70% ethanol
B.10% sodium hypochlorite (bleach), freshly prepared
C.Quaternary ammonium compounds
D.Distilled water
Explanation: Freshly prepared 10% sodium hypochlorite (1:10 dilution of household bleach) chemically degrades DNA by oxidative damage and is the standard decontaminant for molecular labs. After bleach exposure, surfaces should be wiped with 70% ethanol or water to prevent corrosion.
5What is the purpose of UV irradiation of a PCR setup hood between runs?
A.To sterilize the hood of all bacteria
B.To create thymine dimers in any contaminating DNA, preventing amplification
C.To warm the hood
D.To activate fluorescent probes
Explanation: UV-C light induces formation of pyrimidine dimers (thymine-thymine) in any contaminating DNA, blocking polymerase progression and preventing amplification of carryover template. UV is a useful adjunct but does not penetrate plastic well and should supplement (not replace) chemical decontamination.
6Which PPE is REQUIRED at minimum when handling patient blood specimens for nucleic acid extraction?
A.Lab coat only
B.Gloves, lab coat, and eye protection
C.Gloves only
D.Full powered air-purifying respirator (PAPR)
Explanation: Standard precautions for clinical specimens require gloves, a lab coat (or equivalent fluid-resistant gown), and eye protection (or face shield) when there is risk of splashes. This protects against bloodborne pathogen exposure during opening tubes and pipetting.
7What is the recommended workflow direction in a molecular diagnostics laboratory to minimize contamination?
A.Post-amplification area to pre-amplification area
B.Reagent prep to extraction to amplification to detection (one-way)
C.Random movement is acceptable
D.Always start in the detection area
Explanation: Unidirectional (one-way) workflow proceeds from clean to dirty: reagent prep, then specimen extraction, then amplification setup, then detection/post-PCR analysis. Personnel and materials should not move backward, and PPE/lab coats are dedicated to each area.
8Which control is included in a PCR run to demonstrate that reagents and instrument are functioning properly?
A.No-template control (NTC)
B.Positive control with known template
C.Extraction control
D.Internal amplification control
Explanation: A positive control containing known target template demonstrates that reagents, primers, polymerase, and the thermal cycler are working as expected. Failure of the positive control invalidates negative results from the run.
9A lab implements aerosol-resistant (filter) pipette tips. What is their primary benefit?
A.Faster pipetting speed
B.Prevention of pipette barrel contamination by aerosolized template
C.Lower cost than standard tips
D.Better color coding
Explanation: Filter (barrier) tips contain a hydrophobic filter that prevents liquids and aerosols from reaching the pipette barrel, blocking carryover contamination between samples. They are mandatory for pre-PCR pipetting in clinical molecular labs.
10What is the MAIN reason for using uracil-DNA glycosylase (UNG/UDG) with dUTP in clinical PCR assays?
A.To increase polymerase fidelity
B.To prevent carryover amplicon contamination from previous reactions
C.To stabilize primers
D.To reduce reaction time
Explanation: When dUTP replaces dTTP in PCR, all amplicons contain uracil. UNG added at the start of the next reaction cleaves uracil-containing DNA before thermal cycling begins, destroying any carryover amplicons. UNG is then heat-inactivated during initial denaturation so the new amplicons (also dU-containing) remain intact during the run.

About the MDT Exam

AMT specialty credential for molecular diagnostics laboratory professionals. Covers molecular biology theory (DNA/RNA, central dogma), lab procedures (extraction, PCR, qPCR, NGS library prep, gel electrophoresis), genetic diagnostic methods (cytogenetics, FISH, microarray, Sanger), oncology biomarkers (HER2, BCR-ABL, EGFR, BRCA, MSI/TMB, ctDNA), pharmacogenomics (CYP2D6/2C19, TPMT, DPYD, HLA-B*5701), and infectious disease molecular testing (HIV/HCV/HPV/TB/SARS-CoV-2).

Questions

200 scored questions

Time Limit

3 hours

Passing Score

Scaled (AMT-set)

Exam Fee

$210 (AMT)

MDT Exam Content Outline

20%

Molecular Theory

DNA/RNA structure, central dogma, gene expression, base pairing (A-T 2H, G-C 3H)

15%

General Lab Practice

Pre/post-PCR separation, BSL, contamination control, PPE, decontamination

15%

Lab Procedures

Extraction (silica, magnetic beads, Trizol), PCR/qPCR, primer design, gel, NGS library prep

15%

Genetic Diagnostic Methods

Cytogenetics, FISH (HER2, BCR-ABL), microarray, Sanger, NGS bioinformatics

15%

Oncology Diagnostic Methods

Solid tumor + heme malignancy panels, MSI, TMB, MRD, CTC, ctDNA, BRCA, EGFR

15%

Infectious Disease Molecular

HIV viral load, HCV genotype, HPV high-risk, TB GeneXpert, SARS-CoV-2, multiplex panels

5%

Pharmacogenomics

CYP2D6 (codeine), CYP2C19 (clopidogrel), TPMT (azathioprine), DPYD (5-FU), HLA-B*5701 (abacavir)

How to Pass the MDT Exam

What You Need to Know

  • Passing score: Scaled (AMT-set)
  • Exam length: 200 questions
  • Time limit: 3 hours
  • Exam fee: $210

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

MDT Study Tips from Top Performers

1Master PCR thermal profile and primer design (18-25 bp, GC 40-60%, Tm 55-65°C, span exon-exon for cDNA)
2Memorize pre/post-PCR separation (separate rooms, dedicated pipettes, UV decon) — single most important contamination control
3Drill HER2 testing cascade: IHC 0-1 negative, 2+ reflex to FISH, 3+ positive (trastuzumab eligible)
4Know CPIC actionable pharmacogenomics: CYP2D6/2C19, TPMT, DPYD, HLA-B*5701/1502
5Apply Sanger ddNTP chain-termination concept — confirm NGS variants and short defined regions

Frequently Asked Questions

What are the three steps of PCR?

PCR cycles three temperature steps: (1) Denaturation at 94-95°C — separates DNA strands. (2) Annealing at 50-65°C (depends on primer Tm = 4×(G+C) + 2×(A+T) approximation) — primers bind template. (3) Extension at 72°C — Taq polymerase synthesizes new strand. Repeat 25-40 cycles for exponential amplification. qPCR adds fluorescent detection (SYBR Green non-specific OR TaqMan probe specific) with Ct value inversely proportional to template.

What is the difference between FISH and Sanger sequencing?

FISH (Fluorescence In Situ Hybridization) uses fluorescent DNA probes to detect chromosomal translocations, copy number changes, and gene rearrangements at the cellular level (e.g., BCR-ABL in CML, HER2 amplification in breast cancer). Sanger sequencing uses chain-termination ddNTPs to read nucleotide sequence base-by-base — gold standard for confirming variants identified by NGS or for short defined regions.

Which pharmacogenomic markers affect clinical drug selection?

CPIC actionable: CYP2D6 (poor metabolizers — codeine ineffective; tramadol; some antidepressants); CYP2C19 (clopidogrel reduced effect in PMs); TPMT/NUDT15 (azathioprine/6-MP — toxicity risk requires dose reduction); DPYD (5-FU/capecitabine toxicity); UGT1A1*28 (irinotecan); HLA-B*5701 (abacavir hypersensitivity — TEST BEFORE prescribing); HLA-B*1502 (carbamazepine SJS in Asian populations).

How should I study for AMT MDT?

Plan 100-180 hours over 14-18 weeks. Focus on PCR/qPCR mechanics (thermal profile, primer design, Ct interpretation), pre/post-PCR contamination control, and the major diagnostic platforms (FISH, microarray, Sanger, NGS). Memorize CPIC actionable pharmacogenomic markers and infectious disease molecular targets (HIV viral load, HCV genotype, SARS-CoV-2 N/ORF1ab/S genes).