Case definition and testing guidance for COVID-19

The Ministry has developed this case definition and testing guidance for COVID-19 based on expert advice from our Technical Advisory Group.

Last updated: 13 August 2020

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See also: New Zealand COVID-19 Surveillance Plan and Testing Strategy


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 management of clusters. 

The tools available to use are testing, quarantine, self-isolation, and timely contact tracing.

The Ministry has developed testing guidance to support the health sector in testing for COVID-19 to help us identify those with COVID-19 as early as possible. 

  • The highest priority for testing is those who are symptomatic and meet the HIS criteria, all of whom should be tested
  • Table 1 below provides guidance on other groups that are essential to test.
  • All others presenting to health services with symptoms consistent with COVID-19 should also be offered a test – to help ensure that we don’t have community transmission in New Zealand 
  • Only those meeting both the clinical and the HIS criteria will need to be notified to the Medical Officer of Health on presentation
  • Only those meeting both the clinical and the HIS criteria will be asked to self-isolate while awaiting test results.

Case definition

The case definition document no longer defines all who should be tested for COVID-19. The case definition document identifies those with a higher risk of having COVID-19 and outlines the reporting and self-isolation requirements for those with symptoms who meet the higher index of suspicion criteria. Please refer to the testing guidance for advice on who to test to ensure that we do not have community transmission. The testing guidance will be regularly updated, however, those with symptoms who meet the higher index of suspicion criteria should always be the highest priority for testing.

Clinical criteria

The following symptoms are consistent with COVID-19:

Any acute respiratory infection with at least one of the following symptoms: new or worsening cough, sore throat, shortness of breath, coryza 1, anosmia 2 with or without fever.

Some people may present with less typical symptoms such as only: fever, diarrhoea, headache, myalgia, nausea/vomiting, or confusion/irritability. If there is not another likely diagnosis, and they meet the HIS criteria then test.

Higher Index of Suspicion (HIS) criteria

Either, in the 14 days prior to illness onset have:

  • had contact 3 with a confirmed or probable case
  • had international travel
  • had 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, or
  • any other criteria requested by the local Medical Officer of Health

Some people may present with less typical symptoms such as only: fever, diarrhoea, headache, myalgia, nausea/vomiting, or confusion/irritability. If there is not another likely diagnosis, and they meet the HIS criteria then test

This reflects the current COVID-19 situation in New Zealand and that at this stage, our greatest risk of re-introduction of COVID-19 and spread, is via our border. For a definition of close and casual contacts see contact tracing or the Advice for Health Professionals.

Case definition


Testing guidance

Guidance for health practitioners

13 August 2020

It is even more critical that you continue to encourage all patients presenting with symptoms consistent with COVID-19 to be tested, regardless of whether they meet the ‘High Index of Suspicion’ (HIS) criteria or not. This advice applies to people living everywhere in New Zealand.

Areas of New Zealand at Alert level 3 and 4 

At Alert Levels 3 and 4, all people who meet the clinical criteria who are tested should self-isolate while awaiting test results. Only those meeting the HIS criteria need to be notified to the public health unit. 

Areas of New Zealand at Alert level 1 and 2 

At Alert levels 1 and 2, only people who have symptoms and meet the HIS criteria, need to self-isolate while awaiting test results. They should follow the advice of their health practitioner regarding staying at home if unwell. 

Advice for all

Anyone who meets the clinical and HIS criteria should be tested, self-isolate while awaiting test results and be notified to the public health unit. 
Those who meet the HIS criteria who are asymptomatic do not need to self-isolate while waiting for test results, unless they are advised otherwise, for example if they are a close contact of a confirmed case.

Table 1: Guidance for primary and secondary care on essential groups for testing

It is critical that you continue to encourage all patients presenting with symptoms consistent with COVID-19 to be tested.

The assessment and swabbing for these patients are at no charge to the individuals.

We particularly encourage you to test the following groups:

Who Action

Has symptoms of COVID-19 and meets the higher index of suspicion (HIS) criteria, as follows:

In the 14 days prior to illness onset, person has:

  • had contact with a confirmed or probable case
  • had international travel
  • had 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, or
  • any other criteria requested by the local Medical Officer of Health
Test and notify the Public Health Unit. The individual must self-isolate while test is pending. 
Meets the HIS criteria, and has one or more of the following less typical symptoms: fever, diarrhoea, headache, myalgia, nausea/vomiting, or confusion/irritability, and there is not another likely diagnosis. Test and notify the Public Health Unit. The individual must self-isolate while test is pending.

Has symptoms of COVID-19. Does not meet HIS criteria but is:

  • Healthcare worker 
  • Aged care worker 
Test

Has symptoms of COVID-19. Does not meet HIS criteria but is at greater risk of poor health outcomes if they were to contract COVID-19:

  • Māori
  • Pasifika
  • Seniors
  • Pre-existing conditions (for example: chronic obstructive pulmonary disease, high blood pressure, heart disease, diabetes.) 
Test
Asymptomatic border worker groups. This includes those who work at Managed Isolation and Quarantine Facilities.  Test if they present with a referral/letter
Asymptomatic New Zealand-based air crew Test if they present with a referral/letter*

* View more information on requirements for international airline crew.

Guidance for primary and secondary care on essential groups for testing fact sheet

Download Guidance for primary and secondary care on essential groups for testing fact sheet

Surveillance plan and testing strategy


COVID-19 Instructions on specimen collection 

Guidance on how to take nasopharyngeal and oropharyngeal specimens for COVID-19.


1 Coryza – head cold e.g. runny nose, sneezing, post-nasal drip.

2 Anosmia – loss of sense of smell.

3 Refer Advice for Health Professionals for close contact criteria.

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