Evaluating the Analytical Equivalency of Serum and Whole Blood Samples Run on the MeMed Key® Platform (Perseverance Study)

Inclusion Criteria: 1. Written informed consent must be obtained from the patient or his/her legal guardian. For children under 18 years old, written informed consent from the legal guardian must be obtained and assent from the patient may be required depending on the local requirements. 2. Over 90 days of age. 3. Clinical suspicion of acute bacterial or viral infection. 4. Symptoms of acute infectious disease \< 7 days. 5. Experienced fever at least once within the last 7 days (self-reported or Temperature ≥ 37.8°C (100°F)). Exclusion Criteria: 1. HIV, HBV, active HCV, or active Tuberculosis infection (self-declared or known from medical records). 2. Suspicion and/or confirmed diagnosis of infectious gastroenteritis/ colitis. 3. Active inflammatory disease (e.g., IBD, SLE, JIA, RA, Kawasaki, other vasculitis). 4. Pregnancy- self reported or medically confirmed. 5. Active malignancy. 6. Congenital or acquired immune deficiency (CID). 7. A proven or suspected infection on presentation with Mycobacterial (e.g., Tuberculosis, MAC), parasitic or fungal (e.g., Candida, Histoplasma, Aspergillus) pathogen. 8. Significant trauma or burns in the last 7 days. 9. Patients that have undergone major surgery in the last 7 days. 10. Current treatment with immune-suppressive or immune-modulating therapies, including without limitations: 1. Administration of P.O.\\IV\\IM high dose steroids \>1mg/kg/day prednisone (or equivalent) at some point in the past 10 days or daily continuous use of steroids \> 0.25 mg/kg/day in the past 7 days 2. Monoclonal antibodies, anti-TNF agents 3. Intravenous immunoglobulin (IVIG) 4. Cyclosporine, Cyclophosphamide, Tacrolimus, Azathioprine, Methotrexate 5. G/GM-CSF, Interferons.