An interventional study of Metagenomic plasma-based test for agnostic pathogen detection in Infection, Infections, Bacterial and Infections, Fungal, sponsored by Karius, Inc.. Recruiting at 6 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-01-30.
Sponsored by Karius, Inc. · Not applicable, Interventional, and Diagnostic
This clinical trial is designed to evaluate if adding the Karius Spectrum™ plasma test to usual care diagnostic tests, compared to usual care testing alone, among immunocompromised participants presenting with suspected infection in the outpatient setting leads to faster infection diagnosis and treatment. Participants will give a blood sample one time to be used for the testing. Information about the participant's illness and any treatments within 30 days following enrollment will be recorded.
This is a prospective, randomized, controlled interventional trial designed to evaluate the clinical utility and effectiveness of adding the Karius Spectrum™ plasma test to usual care diagnostic tests, compared to usual care testing alone, among immunocompromised participants presenting with suspected infection in the outpatient setting.
The study is structured as a basket trial to enable the efficient evaluation of Karius Spectrum across multiple high-risk clinical populations with shared unmet diagnostic and management needs. The basket protocol outlines core trial elements applicable to all cohorts-including high-level objectives, study design, statistical framework, and operational procedures-while cohort-specific sub-protocols provide detailed rationale, objectives and endpoints, eligibility criteria, and contextual considerations tailored to each cohort. This design supports both pooled analyses across cohorts and subgroup assessments within distinct immunocompromised cohorts.
There are 2 cohorts: Cohort A, which is composed of patients that have had a solid organ transplant; and Cohort B, which is composed of patients that have a hematological malignancy, have had a stem cell transplant, or have undergone CAR-T therapy.
Karius Spectrum is a plasma-based microbial cell-free DNA (mcfDNA) metagenomic sequencing test for agnostic detection, identification, and quantification of more than 1,000 human microbial pathogens (i.e., microorganisms), including bacteria, DNA-based viruses, fungi, and parasites, potentially causing disease anywhere in the body. This test is intended for use in the diagnosis and management of suspected infections.
2,093 studies on the registry are indexed under Infections; 364 are open to participants now.
This study's planned enrollment of 2,000 is above the median of 113 across 1,304 interventional studies indexed under Infections.
Browse Infections studies →Karius, Inc. is the lead sponsor of 10 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Basket Protocol* All participants must meet inclusion
Presenting for evaluation in the outpatient setting (includes telehealth)
*For Participants enrolled in Sub-Protocol A- Solid Organ Transplant*
All Sub-Protocol A subjects must meet the following:
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For Participants enrolled in Sub-Protocol B- Hematological Malignancies and Transplant* All Sub-Protocol B subjects must meet the following:
Exclusion Criteria:
Basket Protocol* All participants must not meet the following:
Any other medical condition that, in the opinion of the treating provider, makes participation undesirable, including but not limited to severe psychiatric illness, etc.
*For Participants enrolled in Sub-Protocol A- Solid Organ Transplant*
All Sub-Protocol A subjects must not meet the following:
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For Participants enrolled in Sub-Protocol B- Hematological and Transplant* All Sub-Protocol B subjects must not meet the following:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.
PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
PD-1, PD-L1 and checkpoint inhibitors
PD-1, PD-L1 and CTLA-4 are proteins that act as brakes on the immune system. Checkpoint inhibitors, such as pembrolizumab or nivolumab, block them so the immune system can attack a cancer.
PD-L1 can also be measured in a tumour sample. Some scores count stained tumour cells only (TPS); others also count certain immune cells (CPS). The study names the score and the minimum it uses.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Relapsed and refractory
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GVHD (graft-versus-host disease)
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
This arm will receive Karius Spectrum test results.
Diagnostic Test: Metagenomic plasma-based test for agnostic pathogen detection
This arm will not receive Karius Spectrum test results.
Karius Spectrum metagenomic plasma-based test.
Time to Identification of a Pathogen Specific Etiology
For each cohort, to evaluate whether the addition of Karius Spectrum testing to usual care testing reduces the time to identification of a pathogen-specific etiology, compared to usual care testing alone, in participants with suspected infection in the outpatient setting.
Time frame: The study sample will be collected within 24 hours of enrollment; participant information including usual care laboratory testing and treatments will be collected for 30 days following enrollment.
Time to Pathogen-Directed Treatment
For each cohort, to evaluate whether the addition of the Karius Spectrum test to usual care testing reduces the time to pathogen-directed treatment compared to usual care testing alone.
Time frame: The study sample will be collected within 24 hours of enrollment; participant information including usual care laboratory testing and treatments will be collected for 30 days following enrollment.
Duration of Antimicrobial Therapy
For each cohort, to evaluate whether the addition of Karius Spectrum testing to usual care reduces the total duration of antimicrobial therapy during the 30-day follow-up period, using data abstracted from the electronic medical record (e.g., medication administration records and provider documentation).
Time frame: 30 days following enrollment.
Percentage of participants receiving pathogen-directed treatment
For each cohort, to evaluate whether the addition of Karius Spectrum testing to usual care testing increases the proportion of participants ultimately receiving pathogen-directed treatment compared to usual care testing alone at specific time points (e.g., Day 3, Day 7, Day 14).
Time frame: 30 days following enrollment.
Time to Clinically Meaningful Detection (CMD)
For each cohort, to evaluate whether the addition of Karius Spectrum testing to usual care testing is associated with a reduction in time to clinically meaningful detection (CMD) compared to usual care testing alone. A CMD event is defined as the earliest identification of either (1) an etiological pathogen, or (2) a non-etiological pathogen that prompts a clinically meaningful action (e.g., treatment initiation, specialist referral, diagnostic escalation, or vascular access removal). Only the first qualifying CMD event per participant will be used for analysis.
Time frame: The study sample will be collected within 24 hours of enrollment; participant information including usual care laboratory testing and treatments will be collected for 30 days following enrollment.
Number of Adverse Events
For all cohorts, the number of participants experiencing adverse events (AEs) and serious adverse events (SAEs) that are unexpected or related to the Karius Spectrum test or study procedures will be assessed. Events will be summarized by type, severity, and relationship to the study intervention.
Time frame: All AEs/SAEs will be collected from the time of blood draw through Day 30.
Plan to share: No
No publications or documents are linked to this record.
Started Oct 2025 (actual). Primary completion is estimated for Sep 2028, 34 months after the start.
Of 305 interventional studies with no phase under Infections, half reached primary completion within 24 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 50. This study's planned 34 months is above that.
Infections covers many different conditions, not one, so the studies compared here vary widely. Read these figures as a rough guide.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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Karius, Inc.