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Companion diagnostics

Precision Medicine

Companion diagnostics

Leverage Quest's expertise in clinical trial assay and companion diagnostic development to ensure you have the best test to support your targeted therapy.
Side view of two young women working in laboratory with microscope.

From concept to commercialization

Expert drug and diagnostics co-development

Using biomarkers to target patients who are more likely to respond to specific therapies has both accelerated and complicated drug development and approval. Quest Diagnostics can help simplify the companion diagnostics (CDx) process.

Your assay choice counts

From initial research and definition through commercialization, you can trust that our industry-leading experts will be with you every step of the way. In collaboration with leading pharmaceutical, biotechnology, and in vitro diagnostic companies, we support companion diagnostic programs with a team that understands clinical development, biomarker assays, regulatory approaches, and commercialization considerations.

Taking your product from bench to bedside

Our experienced regulatory team can support a broad range of submissions, including 510(k) and premarket approval (PMA). We also assist in:

We support every stage of drug development

Asking the right questions to uncover the best answers

Our team includes experts across every step of development, from biomarker assay development to clinical trial assay to companion diagnostic and market access.

We ask the right questions along the way:

  • What test modality maximizes access?
  • What FDA pathway is most favorable?
  • Does the test modality/biomarker align with a commercialization strategy?
  • How will the test result be used to control access? (cutoff)
  • What provides optimal turnaround time?
  • Are you planning on bridging studies or doing a co-development?
  • Do you need a companion diagnostic? Or a complementary diagnostic? Or a laboratory developed test (LDT)?

Our team can help you determine key elements of your development process:

  • Defining the biomarker (eg, specific variants, proteins, antibodies)
  • Selecting the biomarker analyte (eg, DNA, RNA, protein, IgG)   
  • Selecting the specimen type (eg, serum, saliva, tissue)
  • Selecting the technology (eg, next generation sequencing (NGS), polymerase chain reaction (PCR), immunohistorychemistry (IHC), enzyme-linked immunoassay (ELISA))
  • Selecting the cutoff (eg, number)

Therapeutic expertise

When it comes to developing and deploying companion diagnostics, our experts lead the way in today’s novel therapeutics. Quest Diagnostics has partnered with pharma companies to provide precision medicine solutions across a wide range of disease areas. Our team works closely with you on considerations for the design of your biomarker program.


  • Gene therapy and adeno-associated viruses (AAVs)
  • Cancer and immuno-oncology
  • Neurodegenerative diseases
  • Rare and complex genetic diseases
  • Infectious diseases
  • Genitourinary diseases
  • Autoimmune disease
  • Safety
  • Diagnostic
  • Prognostic/predictive
  • Pharmacodynamics
  • Disease management
  • Monitoring of response
  • Intended use population (atient identification/stratification)
  • Eligibility criteria (Inclusion/exclusion)
  • Patient care: Safe and effective use of the drug
  • Monitoring
  • Single site versus multi-site use
  • Technology used
  • PCR
  • Next generation sequencing
  • Immunohistochemistry
  • In situ hybridization
  • Flow cytometry
  • Immunoassays
  • Cell-based assays
  • Liquid chromatography–mass spectrometry (LC-MS)

Let’s discuss your project

Learn how our companion diagnostic development expertise can advance your clinical development program.

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Let's discuss your next project

Connect with our team of experts today.

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