Diagnostic Application: Pneumonia

Bronchoscopy can fail to yield a diagnosis in 50% - 75% of procedures in immunocompromised patients.1-4

Featured Case

Study Site: OSF Saint Francis Medical Center5

39 years old with untreated HIV infection and respiratory failure requiring mechanical ventilation with an unclear etiology.

Tests Performed: Diagnostic tests performed for evaluation of pneumonia and other etiologies included absolute CD4 count of 6, HIV viral load of 332,909 copies/ml, CMV IgG positive; CXR with bilateral multinodular changes, chest CT with miliary lesions, brain MRI with multiple ring enhancing lesions; negative testing included: blood and BAL cultures; VZV, syphilis, and tuberculosis studies; Histoplasma/ Aspergillus/ Legionella/ Cryptococcus/ Influenza antigens.

(A) CT chest axial lung window showing miliary changes in both lungs; (B) CT chest axial lung window showing several nodules with developing central cavitation and bilateral consolidation; (C) coronal window showing bibasilar airspace disease with confluent consolidation throughout the lung bases5

Karius Test Result: Toxoplasma gondii

Outcome: Started 6-week course of pyrimethamine/sulfadiazine, discontinued piperacillin/tazobactam; resulting in significant clinical improvement allowing the patient to be started on antiretroviral therapy.

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Clinical Evidence

Study Site: 10 Medical Centers*

In a prospective, multi-center study enrolling over 173 adult patients with suspected pneumonia, a 40% (21/52) relative increase in the cause of pneumonia identified when the Karius Test was used in conjunction with standard of care (SOC) testing.**,6

Moreover, the primary endpoint was achieved: 1 in 6 patients (21/121) had a cause of pneumonia identified via the Karius Test where a thorough SOC of 15+ tests did not. 81% (17/21) of these patients would have had an adjudicated possible antimicrobial change with the Karius Test result where SOC failed.**,6

*Please see PICKUP Study Summary for full list of enrolling centers
**Please see study for comparable tests


Study Site: Rady Children’s Hospital

In a retrospective study in 46 immunocompetent pediatric patients with complicated community acquired pneumonia, the Karius Test led to a change in antimicrobial management in 78% (35/46).7

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Considerations for Use

Learn More About the Karius Test

*KT is an LDT. Clinicians should independently evaluate its use and interpret test results. This content is provided for informational purposes only and is not intended or implied to be an exhaustive list of consideration or substitute for existing medical expertise or guideline recommendations.

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Bergin, SP et al, Plasma Microbial Cell-Free DNA Sequencing in Immunocompromised Patients with Pneumonia: A Prospective Observational Study, Clinical Infectious Diseases, 2023;, ciad599, https://doi.org/10.1093/cid/ciad599
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