What are the steps for testing and treating SARS coronavirus 2 (Severe Acute Respiratory Syndrome coronavirus 2) (COVID-19)?

Testing and Treatment Protocol for SARS-CoV-2 (COVID-19)

For optimal patient outcomes, standard nucleic acid amplification testing (NAAT) is recommended as the first-line diagnostic test for symptomatic individuals suspected of having COVID-19, followed by appropriate treatment based on risk factors and disease severity.

Diagnostic Testing Algorithm

For Symptomatic Individuals:

1. Initial Testing Approach:

   • Standard NAAT (RT-PCR) is strongly recommended as the first-line test for symptomatic individuals 1
   • If standard NAAT results would be delayed >24 hours, use rapid antigen testing instead 1
   • For optimal performance, antigen tests should be performed within 5 days of symptom onset 1

2. Specimen Collection Options:

   • Acceptable specimens for NAAT (in order of preference):
     • Nasopharyngeal (NP) swab (highest sensitivity)
     • Midturbinate (MT) swab
     • Combined anterior nasal (AN) plus oropharyngeal (OP) swab
     • Saliva or mouth gargle specimens 1
   • Note: OP swabs alone have a much lower detection rate (73.1% of NP positive cases were negative by OP swab) 1

3. Self-Collection Options:

   • Anterior nasal and midturbinate specimens can be either self-collected or collected by healthcare providers 1
   • For self-collection, either observed or unobserved collection is acceptable with proper instructions 1

4. Interpretation of Results:

   • Positive NAAT: Confirms infection, no need for confirmatory testing
   • Negative NAAT with high clinical suspicion: Consider repeat testing
   • Positive antigen test: High specificity allows for treatment decisions without confirmation 1
   • Negative antigen test with moderate/high clinical suspicion: Confirm with standard NAAT 1

For Asymptomatic Individuals with Known Exposure:

1. Testing Timing:

   • Test at least 5 days after exposure
   • If symptoms develop before 5 days, test immediately 1

2. Testing Approach:

   • Standard NAAT is preferred over antigen testing 1
   • If NAAT results would be delayed, use antigen testing 1

Treatment Protocol for Confirmed COVID-19

For Non-Hospitalized Patients with Mild-to-Moderate COVID-19:

1. Risk Assessment:

   • Identify patients at high risk for progression to severe disease

2. Treatment Options for High-Risk Patients:

   • Remdesivir (Veklury): FDA-approved for non-hospitalized patients with mild-to-moderate COVID-19 at high risk for progression 2
     • Adult and pediatric patients ≥40kg: 200mg IV on Day 1, followed by 100mg IV once daily from Day 2
     • Pediatric patients <40kg: Weight-based dosing (see table below)
     • Treatment should be initiated as soon as possible after diagnosis 2

   Weight-Based Dosing for Pediatric Patients:

   Patient Population	Loading Dose	Maintenance Dose
   <28 days old, ≥1.5kg	2.5 mg/kg	1.25 mg/kg once daily
   ≥28 days, 1.5kg to <3kg	5 mg/kg	2.5 mg/kg once daily
   ≥28 days, 3kg to <40kg	5 mg/kg	2.5 mg/kg once daily

For Hospitalized Patients:

1. Treatment Options:

   • Remdesivir (Veklury):
     • For patients not requiring mechanical ventilation/ECMO: 5-day course
     • For patients requiring mechanical ventilation/ECMO: 10-day course
     • If no clinical improvement after 5 days, may extend treatment for up to 5 additional days 2

2. Monitoring During Treatment:

   • Perform hepatic laboratory testing in all patients before starting and during treatment
   • Determine prothrombin time before starting and monitor as clinically appropriate 2
   • Monitor for infusion or hypersensitivity reactions 2

Important Considerations and Caveats

1. Testing Limitations:

   • False negatives with RT-PCR: During the 4 days of asymptomatic infection, false-negative rates range from 100% on Day 1 to 68% on Day 4 1
   • Optimal testing time: 3 days after symptom onset (minimizes false-negative rate to 20%) 1
   • Antigen tests have lower sensitivity than NAAT, especially in asymptomatic individuals or late in infection 1, 3

2. Treatment Considerations:

   • Remdesivir should only be administered in settings with immediate access to medications for treating severe reactions 2
   • Do not use remdesivir to guide discontinuation of isolation or prior to procedures/surgery 1

3. Follow-up Testing:

   • Repeat testing is not recommended to determine end of isolation period 1
   • For patients who have recovered from COVID-19, IgM/IgG testing can provide evidence of clearance 1

By following this evidence-based algorithm for testing and treatment, clinicians can optimize diagnosis and management of COVID-19 to reduce morbidity and mortality while efficiently utilizing healthcare resources.