Case definition and clinical testing guidelines for COVID-19

Case definition and clinical testing guidelines for health practitioners

Last updated: 16 April 2021

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See also: Testing plan and testing guidance


Strategic tools for early identification and management

The overarching public health COVID-19 strategy for New Zealand is to eliminate COVID-19. We must identify and manage cases and contacts early and be aggressive with the containment and management of clusters. 

The tools available to use are:

  • effective public messaging
  • testing
  • timely contact tracing 
  • self-isolation or managed isolation/quarantine

The Ministry has developed the clinical guidelines for testing, below, to support the health sector in identifying those with COVID-19 as early as possible. 

  • The highest priority for testing is those who are symptomatic and who meet the High Index of Suspicion (HIS) criteria or are contacts of confirmed (or probable) cases, all of whom should be tested.
  • Table 1 provides guidance for testing in primary care. It is critical to encourage all people presenting with symptoms consistent with COVID-19 to be tested.
  • Table 2 provides guidance for testing in hospitals including emergency departments.
  • The assessment and swabbing for those covered by this guidance is at no charge to the individuals. Refer advice for the border sector for information on those covered by routine mandatory testing. 
  • DHBs may operate ‘pop-up’ testing facilities in the community, including for additional testing of asymptomatic people.
  • Information on testing locations can be found on the Healthpoint website.

Clinical symptoms consistent with COVID-19

The following symptoms are consistent with COVID-19:

Any acute respiratory infection with at least one of the following symptoms (with or without fever):

  • new or worsening cough
  • sore throat
  • shortness of breath
  • coryza – head cold (eg, runny nose, sneezing, post-nasal drip)
  • anosmia – loss of sense of smell.

Less typical symptoms:

  • Some people may present with less typical symptoms such as only fever, diarrhoea, headache, myalgia (muscle aches), nausea/vomiting, or confusion/irritability.
  • If there is not another likely diagnosis, and they meet the HIS criteria or are contacts of a confirmed (or probable) case, then test. 

Case definition


Clinical guidelines for testing

Testing should be prioritised in people who:

  • are symptomatic
  • and/or meet the Higher Index of Suspicion criteria below
  • and/or are contacts of confirmed (or probable) cases who also meet clinical criteria for COVID-19.

For definitions of contacts (e.g. Close Plus, Close, Casual Plus and Casual Contacts) see Contact tracing.

Higher Index of Suspicion (HIS) criteria

A higher index of suspicion for COVID-19 is indicated if any of the following are met in the 14 days prior to illness onset:

  • international travel
  • direct contact with a person who has travelled overseas (eg, Customs and Immigration staff, staff at quarantine/isolation facilities)
  • worked on an international aircraft or shipping vessel
  • cleaned at an international airport or maritime port in areas/conveniences visited by international arrivals
  • exited an MIQ facility (excluding recovered cases)
  • worked in a cold store facility that receives imported chilled and frozen goods directly from an international air or maritime port
  • any other criteria requested by the local Medical Officer of Health.
Table 1: Testing in primary care and community

Presentation

Action

Symptomatic

Higher index of suspicion

Typical symptoms

  • Test
  • Notify the Medical Officer of Health
  • Self-isolate1 while test result is pending and until 24 hours after symptoms resolve and cleared by a health official

Less typical symptoms with no other likely diagnosis

Close/Close Plus Contact

Typical symptoms

  • Test immediately, and on day 5, and day 12 following exposure.
  • Notify the Medical Officer of Health
  • Self-isolate1 for 14 days following exposure and until released by public health official

Casual Plus Contact

Typical symptoms

  • Test immediately and on or about day 5
  • Stay at home2 until day 5 test result is pending and until 24 hours after symptoms resolve.
  • If symptoms develop after day 5, test and stay at home while test result is pending.

Casual Contact

Typical symptoms

  • Test
  • Stay at home2 while test result is pending and until 24 hours after symptoms resolve

Not higher index of suspicion or contact

Typical symptoms

  • Test
  • Stay at home2 while test result is pending and until 24 hours after symptoms resolve

Asymptomatic

Close/Close Plus Contact

  • Test as per advice from Ministry of Health and/or public health unit on day 0 (immediate), day 5 and day 12
  • Self-isolate1 for 14 days and until released by public health official

Casual Plus Contact

  • Test on day 5
  • Stay at home2 while test result is pending

Casual Contact

  • No test required unless symptoms develop.
  • Self-monitor for COVID-19 symptoms for 14 days.

Surveillance testing: Border worker including managed isolation or quarantine facilities

  • Test as per Border Order3
  • No need to isolate following a surveillance test, unless they also meet any Close/Close Plus or Casual/Casual plus criteria as described above.

Surveillance testing: New Zealand-based air crew

  • Test as per requirements4
  • No need to isolate following a surveillance test, unless they also meet any Close/Close Plus or Casual/Casual plus criteria as described above.
  1. More information is available under Self-isolation guidance.
  2. More information is available under Staying at home
  3. More information on Border Orders is available at Epidemic notice and Orders.
  4. More information on requirements for international airline crew is available at Aviation sector.
Table 2: Testing in hospital including emergency departments

Presentation

Action

Symptomatic

Higher index of suspicion or a contact

Typical symptoms

  • Test1
  • Notify the Medical Officer of Health
  • Isolate while test result is pending and until clearance

Less typical symptoms with no other likely diagnosis

Not at higher index of suspicion or a contact

Typical symptoms

  • Test1
  • Manage as per local infection prevention and control protocols
  1. Testing can be omitted if on clinical assessment there is another clear cause, not a transmissible respiratory infection.

Self-isolation guidance and notification to a public health unit

Anyone who is tested should stay home while awaiting their test results.

Anyone who meets the clinical and HIS criteria should be tested, self-isolate from their household while awaiting test results and be notified to the public health unit.

Read more about self-isolation at home or staying at home.

Household members of Close Plus Contacts

  • Close Plus Contacts meet the same criteria for Close Contacts however, their contact was where there is higher risk for transmission. 
  • All household members (and others at the discretion of the Medical Officer of Health) should stay at home until the Close Plus Contact has a negative day 5 test result.
  • If the Close Plus Contact develops symptoms after day 5, all household members should stay at home until a further negative test result is received for the Close Plus Contact.

Household members of Close Contacts

  • If the Close Contact becomes symptomatic, then their household members should stay at home until the Close Contact returns a negative test result (following symptom onset)
  • If one or more household member(s) becomes symptomatic, they should stay at home and get a test
  • If the Close Contact is asymptomatic, the household members do not have to stay at home. 

Testing plan and testing guidance

View the Testing plan and testing guidance.


COVID-19 Instructions on specimen collection 

Guidance on how to take nasopharyngeal, and oropharyngeal + anterior nasal specimens for COVID-19.

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