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Tempus xF Liquid Biopsy

Tempus xF is a 105-gene liquid biopsy ctDNA seq panel that detects oncogenic drivers and resistance mutations, assesses for MSI, and identifies SNVs, INDELs, and CNVs, all of which help inform precision medicine decisions.


Tissue and liquid testing helps to maximize data and account for tumor heterogeneity, helping to expand treatment strategies for patients.

Non-overlapping actionable gene alterations:

  • Data suggests that non-overlapping actionable gene alterations and resistance mechanisms may be detected using complementary tissue and liquid biopsy testing approaches.1,2,3

Tumor tissue is limited or unavailable:

  • 74% of clinically actionable variants† identified by xT solid tumor NGS were also detected by xF liquid biopsy,4 making it a valuable option for providing genomic results when tumor tissue is limited or unavailable by assessing ctDNA from peripheral blood.

May detect additional actionable variants:

  • 9% of patients had unique actionable alterations found in liquid biopsy that were not detected in solid tumor alone, in a pan-cancer analysis of 1315 patients with actionable variants.5


xF can also monitor common resistance mechanisms arising from frontline targeted therapies in several cancer types, including lung, breast, ovarian, and colorectal cancers.

  • EGFR & ALK resistance mutations in lung cancer 6,7
  • ESR1 mutations in breast cancer 8
  • BRCA1/2 reversion alterations in ovarian and breast cancer 9
  • Anti-EGFR resistance mechanisms in colorectal cancer 10


7 days from specimen retrieval

Ordering Flexibility

Tempus offers a variety of options to customize molecular profiling for patients.

  • xF may be ordered as a standalone test or in combination with solid tumor
  • Longitudinal testing using xF Liquid Biopsy
  • Auto-conversion from xT Solid Tumor/Normal Match to xF Liquid Biopsy in the event of insufficient tissue
  • Streamlined ordering process through Tempus Hub, paper requisition, or directly from your EHR
Access Tempus Hub


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    xF Gene List


    Specimen Guidelines


xF Performance Specifications

Variant Class Variant Allele Fraction (VAF) Sensitivity Specificity
Single Nucleotide Variants (SNVs) >0.50%
Insertions and Deletions >0.50%
Copy Number Amplifications (CNAs) >0.50%
Rearrangements/Fusions >0.50%
Microsatellite Instability High (MSI-H) Status N/A 37.5% >99.9%

All numbers shown at 30 ng input DNA quantity.

Financial Assistance

We help provide access to our tests for all patients in financial need

Approval of the financial assistance application is based on your household income and takes into account all life circumstances. Once a financial assistance application is submitted either online or over the phone, you will receive a decision at the time of submission. 

  • Step 1

    Apply for financial assistance online at

  • Step 2

    If approved, you will know immediately about the maximum out-of-pocket cost of your testing.

  • Step 3

    Please contact if you are concerned about out-of-pocket costs and would like to discuss your options.

    All U.S.-based patients are eligible to apply for financial assistance regardless of insurance status. For uninsured and international patients, we offer a self-pay option. If you have any questions, please email

  1. Chae YK, Davis AA, Carneiro BA, et al. Concordance between genomic alterations assessed by next-generation sequencing in tumor tissue or circulating cell-free DNA. Oncotarget. 2016;7(40):65364-65373.
  2. Aggarwal C, Thompson JC, Black TA, et al. Clinical implications of plasma-based genotyping with the delivery of personalized therapy in metastatic non-small cell lung cancer. JAMA Oncol. 2019;5(2):173-180.
  3. Parikh AR, Leshchiner I, Elagina L, et al. Liquid versus tissue biopsy for detecting acquired resistance and tumor heterogeneity in gastrointestinal cancers. Nat Med. 2019;25(9):1415-1421.
  4. Finkle JD, Boulos H, Driessen TM, et al. Validation of a liquid biopsy assay with molecular and clinical profiling of circulating tumor DNA. npj Precis. Oncol. 2021;5(1):63.
  5. Based on a retrospective study involving a cohort of randomly selected patients with breast cancer, CRC, NSCLC, and prostate cancer. Mackay M, Mitsiades N, Chae YK, et al. Dual tissue and plasma testing to improve detection of actionable variants in patients with solid cancers. J Clin Oncol. 2022;40(16_suppl):3017.  All analyses were limited to variants that met the limit-of-detection criteria for both xT and xF (104 genes). Actionability was defined as indication-matched variants with OncoKB Level 1, 2 or R1 evidence.
  6. Jenkins S, Yang JCH, Ramalingam SS, et al. Plasma ctDNA analysis for detection of the EGFR T790M mutation in patients with advanced non-small cell lung cancer. J Thorac Oncol. 2017;12(7):1061-1070.
  7. Horn L, Whisenant JG, Wakelee H, et al. Monitoring therapeutic response and resistance: analysis of circulating tumor DNA in patients With ALK+ lung cancer. J Thorac Oncol. 2019 Nov;14(11):1901-1911.
  8. Bidard FC, Hardy-Bessard AC, Dalenc F, et al. Switch to fulvestrant and palbociclib versus no switch in advanced breast cancer with rising ESR1 mutation during aromatase inhibitor and palbociclib therapy (PADA-1): a randomized, open-label, multicentre, phase 3 trial. Lancet Oncol. 2022;23(11):1367-1377.
  9. Lin KK, Harrell MI, Oza AM, et al. BRCA reversion mutations in circulating tumor DNA predict primary and acquired resistance to the PARP inhibitor rucaparib in high-grade ovarian carcinoma. Cancer Discov. 2019 Feb;9(2):210-219. Doi: 10.1158/2159-8290.CD-18-0715.
  10. Sartore-Bianchi A, Pietrantonio F, Lonardi S, et al. Circulating tumor DNA to guide rechallenge with panitumumab in metastatic colorectal cancer: the phase 2 CHRONOS trial. Nat Med. 2022;28(8):1612-1618.

† “Clinically actionable variants” are assessed as part of the Tempus report generation pipeline.

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