Guidance on When to Obtain a Second Test for SARS-CoV2

Guidance on who should be tested for SARS-CoV-2 has been updated to include information on when providers should consider sending a second test from patients who have had one test that is negative.  Generally speaking, a second test should be reserved for patients for whom there is a high level of concern for COVID-19.

Rationale for obtaining a 2nd testing during a course of illness:

  • Well-designed PCR tests for SARS-CoV2 have high analytical sensitivity, but clinical sensitivity is unknown due to lack of clinical gold standard.
  • Clinical sensitivity is dependent on where the patient is in the course of their illness and the associated viral load (viral load decreases later in the course of illness).
  • SARS-CoV2 appears to have anatomical tropism. For instance, in general, shedding persists for longer in lower respiratory tract specimens and as a result, lower respiratory tract specimens have higher sensitivity than upper respiratory tract specimens.
  • Our testing strategy at Seattle Children’s calls for utilizing upper respiratory tract specimens as the primary specimen because it is not always possible and is often not easy to obtain a lower tract specimen from a pediatric patient.
  • However, when suspicion for SARS-CoV2 disease (COVID-19) is high, consideration should be given to obtaining a second test and preferably from the lower respiratory tract if possible.

Procedure:

Identify which patients have a higher pretest probability of COVID-19:

  • Rapid or severe respiratory decompensation without alternate explanation with or without chest CT findings consistent with COVID-19

OR

  • Lower respiratory tract disease (cough, increased RR, SOB, or 02 requirement) without another etiology

AND one of the following:

    • Close contact exposure to known COVID+

OR

    • Patient lives in facility / group home

OR

    • Radiological evidence consistent with COVID-19 (CXR: bilateral infiltrates, not lobar consolidation; CT: ground glass opacities)

Preferred 2nd samples:

  • Productive cough: collect sputum if possible
  • No cough or non productive cough:
    • Preferred specimens: induced sputum, deep suctioning through ETT, BAL
    • If above not possible or feasible: consider repeating middle turbinate (MT) swab or other upper respiratory tract sampling

Isolation Considerations based on 2nd SARS-CoV2 test results:

  • Lower respiratory tract specimen
    • Positive: SIU
    • Negative: Can transition to viral respiratory precautions (due to pre-existing respiratory symptoms/signs)
  • Repeat MT swab or other upper respiratory tract sampling
    • Positive: SIU
    • Negative:
      • High index of suspicion of COVID-19: remain in SIU
      • Lower index of suspicion of COVID-19: discuss with ID to consider whether strict isolation or viral respiratory isolation outside SIU is appropriate.

Update on SARS-CoV-2 Antibody Testing at Seattle Children’s

Seattle Children’s leadership has been closely following developments in available antibody testing for SARS-CoV-2, the virus that causes COVID-19. Several new tests have entered the market using the Food and Drug Administration’s Emergency Use Approval status. These tests vary widely in their performance, and we are cautiously evaluating one of these platforms (the same platform that UW recently began using) to perform at Seattle Children’s.

It is important to validate the specificity of these tests to ensure that antibodies to other coronavirus strains do not interfere with results. Additionally, Seattle Children’s leaders are discussing algorithms for this testing and guidance will be forthcoming.

 

Grace Period for Life Support Certifications Extended, Classes Paused

The American Heart Association has issued an extension of the previously announced 60-day grace period for all life support certifications. Providers can now continue working up to 120 days beyond expiration of their certification.

Based on this information and guidance from the Centers for Disease Control and Prevention (CDC), Seattle Children’s will not be holding the following courses through the end of May: Basic Life Support (BLS); Neonatal Resuscitation Program (NRP); Pediatric Emergency Assessment, Recognition and Stabilization (PEARS); Cardiopulmonary Resuscitation (CPR); Advanced Cardiovascular Life Support (ACLS); and Pediatric Advanced Life Support (PALS). We will keep you apprised of any future changes and plans to resume classes.

Help Us Remind Families About the Importance of Emergency Care 

Seattle Children’s has experienced a significant decrease in patients coming to the Emergence Department. Please help us remind families that if their child needs emergency care, not to delay taking them to the emergency department. Delaying care for potentially serious concerns can put their child at risk for more severe complications. Families can learn more about COVID-19 safety at Seattle Children’s in this brief video.

COVID-19 Testing Update as of Tuesday, April 28

Patients tested to date: 2,311. Positive: 22. Inconclusive: 7. The positivity rate is therefore 1.3%. All patients who tested positive are recovering at home.

For more information, visit our Provider FAQs for COVID-19.