Technical Notes: Glossary

African, Caribbean or Black (ACB) people
One of Ontario’s priority populations. Diagnoses attributed to ACB are defined by having indication of being born in an African or Caribbean country and/or Black race/ethnicity. See Priority populations for more information.

Anonymous HIV testing
A type of non-nominal HIV diagnostic testing where no identifying information on the individual being tested is collected on the test requisition form. The lack of identifying information means that it is not possible to link anonymous HIV-positive diagnostic tests to viral load tests within the HIV Datamart.

Coded HIV testing
A type of non-nominal HIV diagnostic testing where a code, instead of the name of the individual being tested, is collected on the test requisition form. The lack of identifying information means that it is not possible to link coded HIV-positive diagnostic tests to viral load tests within the HIV Datamart.

Gay, bisexual, and other men who have sex with men (GBMSM)
One of Ontario’s priority populations. Diagnoses attributed to GBMSM are defined by having reported ‘Male’ or ‘Transgender male’ sex, and sexual contact with men as an HIV risk factor. See Priority populations for more information.

First-time HIV diagnoses
First-time HIV diagnoses are positive HIV tests with no previous evidence of HIV. We look at this number to better understand which diagnoses are likely due to local transmission in Ontario and, therefore, what populations might be at most risk and benefit most from prevention activities. We report on first-time HIV diagnoses separately to better understand local transmission.

First-time HIV diagnoses exclude anyone with a previous positive diagnostic test as indicated on the LEP form (or the test requisition form since 2018), regardless of the location of the previous positive test (inside of outside of Ontario). It also uses linked viral load testing history in Ontario as evidence of being in care for HIV so excludes 1) anyone with a history of viral load testing in Ontario of more than 30 days before to their first nominal confirmatory diagnostic test in Ontario, or 2) anyone with a history of viral load testing in Ontario within 30 days (including same day) of their first nominal confirmatory diagnostic test with a viral load of <200 copies/mL indicating prior treatment. People who have evidence of a history of viral load testing before their first reported HIV positive test are counted as a positive HIV test in the first year which there is evidence of an HIV diagnoses (i.e. the year of their first viral load test).

Health regions
Groupings of public health units that have historically been used in HIV epidemiology and surveillance reports. There are seven health regions: Northern, Ottawa, Eastern, Toronto, Central East, Central West and Southwest. See Health regions for more information on these groupings and boundaries.

HIV Datamart
All OHESI data is stored in the HIV Datamart, an integrated data platform composed of Public Health Ontario Laboratory’s diagnostic and viral load testing databases. Within the Datamart, diagnostic and viral load test records are linked together for the same person (however, linkage is not possible for anonymous and coded HIV-positive diagnostic tests).

HIV exposure category
A category meant to represent an individual’s most likely means of HIV acquisition. An individual getting tested is assigned to an exposure category based on reported “HIV risk factors” (defined below) collected on the test requisition form. Exposure categories are mutually exclusive, which means an individual can only be assigned to one category. When more than one exposure category is applicable for a single individual, a hierarchy is used to assign them to a single category. This hierarchy is based on the level of HIV risk associated with different exposure categories. See HIV exposure categories for more information.

HIV risk factor
A factor reported on the HIV test requisition form and/or the LEP form that relates to an individual’s potential route(s) of HIV acquisition. HIV risk factors are used to define both HIV exposure categories and HIV priority populations. They are not mutually exclusive (as many as are applicable can be selected) and include: sexual contact with women; sexual contact with men; injection drug use; having been born in an HIV-endemic country (includes countries in sub-Saharan Africa and the Caribbean); being a child of HIV-positive mother; sex with a person who was known to be HIV-positive; sex with a person who was known to be using injection drugs; sex with a person who was known to be born in an HIV-endemic country (includes countries in sub-Saharan Africa and the Caribbean); and sex with a person who was known to be a bisexual male (for female individuals).

HIV-positive diagnostic test
Defined as a blood sample that has initially tested reactive on a screening test (either at the laboratory or on a point-of-care / rapid test), and has been confirmed as HIV-positive by a separate test (Western Blot, p24 antigen confirmatory test, or polymerase chain reaction for children <18 months). HIV-positive diagnostic tests in the HIV Datamart includes all people who were diagnosed with HIV. That is, people who test HIV-positive for the first time in Ontario (never tested HIV-positive out-of-province), as well as people who were diagnosed HIV-positive elsewhere and moved to Ontario and tested again (‘out-of-province’ diagnoses).

HIV test positivity rate

The percent of HIV diagnostic tests with a confirmed HIV-positive result. HIV test positivity rates can provide insight into which sub-populations have a higher level of HIV risk. However, HIV test positivity rates should be interpreted with the awareness that although they are calculated with the counts of first-time diagnoses, some of the diagnoses likely still represent individuals with prior knowledge of their HIV-positive status who are unable to be identified in the HIV Datamart. See « HIV testing in Ontario, 2019 » for more information.

HIV test with previous evidence of HIV

An HIV test with previous evidence of HIV includes any individual with a previous positive diagnostic test as indicated on the test history section of the laboratory enhancement program (LEP) form or the test requisition form, regardless of the location of the previous positive test (inside or outside of Ontario). It also uses linked viral load testing history in Ontario as evidence of being in care for HIV and so excludes 1) anyone with a history of viral load testing in Ontario of more than 30 days before a first diagnostic positive test and 2) anyone with viral load testing in Ontario within 30 days (including same day) with a viral load <200 copies/ml. For HIV tests with previous evidence of HIV, the HIV test is assigned to the year the test was performed (denominator of HIV test positivity rate calculation), while the positive HIV diagnosis is assigned to the year where the previous evidence of HIV is first documented (numerator of HIV test positivity rate). See « HIV testing in Ontario, 2019 » for more information.

Indigenous Peoples
One of Ontario’s priority populations. Diagnoses attributed to Indigenous Peoples are defined by having the ‘First Nations’, ‘Inuit’, and/or ‘Métis’ race/ethnicity reported. See Priority populations for more information.

Integrated Public Health Information System (iPHIS)
iPHIS is an electronic, web-based system used by public health units (PHUs) for case-management and reporting to the Ontario Ministry of Health on diseases of public health significance, including HIV. It is the main source of data used by PHUs and Public Health Ontario to produce reportable disease surveillance reports. iPHIS includes information elicited during public health follow up of HIV cases. iPHIS data are not used in OHESI products.

Laboratory Enhancement Program (LEP)
When a person receives a new HIV diagnosis in Ontario, a Laboratory Enhancement Program (LEP) form is sent to the health care provider who ordered the test in order to collect further information on the person who tested HIV-positive. This includes information collected on the original test requisition (e.g. risk factors), as well as additional information. Since 2009, the LEP form has collected information on race/ethnicity and country of birth.

Nominal HIV testing
A type of HIV diagnostic testing where the test requisition form contains the name of the individual being tested. Nominal HIV tests can be linked to viral load tests in the HIV Datamart using patient identifiers.

Non-nominal HIV testing
A type of HIV diagnostic testing where the test requisition form does not contain the name of the individual being tested. There are two types of non-nominal testing in Ontario: anonymous and coded. The lack of identifying information means that it is not possible to link non-nominal HIV-positive diagnostic tests to previous diagnostic tests and viral load tests within the HIV Datamart.

People who use injection drugs (PWID)
One of Ontario’s priority populations. Diagnoses attributed to PWID are defined by having reported injection drug use as an HIV risk factor. See Priority populations for more information.

Point-of-care (POC) testing
HIV diagnostic testing that provides initial results at the same visit as the test. The rapid test currently used in Ontario can provide results within minutes. Rapid testing was first introduced in Ontario in 2007. Rapid tests are provided to all 38 currently active anonymous testing organizations as well as four other organizations that are not legislated to provide anonymous testing. If a POC test is reactive (i.e. suggestive of an HIV-positive result), the result is not considered to be a final diagnosis. To confirm the result, a blood sample must be taken and sent to the laboratory for additional testing. If a POC test is non-reactive, it is included in the total testing numbers as a negative test. OHESI reports POC tests provided by the Ministry of Health (MOH) only.

Positive HIV tests
Positive HIV tests includes all unique individuals (i.e. only one test for each individual) receiving a confirmed HIV-positive diagnosis in Ontario. This includes individuals who have previously tested positive for HIV outside of Ontario, but does not include individuals who have previously tested positive for HIV in Ontario. It also includes individuals who have a history of viral load testing in Ontario without a recorded and linked prior confirmatory diagnostic test in Ontario. Only the first positive test in Ontario is included toward the positive HIV tests counts.

A reactive rapid/point-of-care test result (i.e. suggestive of an HIV-positive result) must be confirmed through laboratory testing to be counted as a Positive HIV Test. Individuals with a previous record of an HIV-positive test within Ontario are excluded to prevent double-counting. The LEP is used to remove tests which cannot be linked by identifying information on the requisition form, but are indicated as a repeat test. This will remove many additional duplicates, but if repeat test information is missing or not reported, or a patient tests HIV-positive more than once through non-nominal testing, duplicate tests will still remain.

Individuals with a positive HIV test include: 1) first-time HIV diagnoses and 2) people who have previous evidence of HIV. Individuals with previous evidence of HIV either 1) had an HIV-positive diagnoses outside of Ontario and later retested in Ontario (as recorded on the test history section of the laboratory enhancement program (LEP) case report or the test requisition form), or 2) had a history of viral load testing in Ontario more than 30 days prior to their first nominal confirmatory diagnostic test in Ontario, or 3) had a history of viral load testing in Ontario within 30 days (including same day) of their first nominal confirmatory diagnostic test with a viral load of <200 copies/mL indicating prior treatment. People who have evidence of a history of viral load testing before their first reported HIV positive test are counted as a positive HIV test in the first year which there is evidence of an HIV diagnoses (i.e. the year of their first viral load test).

Prenatal HIV test

An HIV test that was done either as part of a prenatal screening requisition form or a regular HIV test requisition form with ‘Prenatal’ checked as the reason for testing.

Previous evidence of HIV (PEH)
Positive HIV tests with previous evidence of HIV represent unique individuals (i.e. only one test for each individual) include both 1) people who may be new to the province who already knew their HIV-positive status and have a confirmatory HIV test in Ontario (‘out-of-province’ HIV diagnoses) and 2) people who may have been infected in Ontario and have been living and receiving care (viral load testing) in the province but have no prior linked confirmatory diagnostic test in Ontario. People who have evidence of a history of viral load testing before their first reported HIV positive test are counted as a positive HIV test in the first year which there is evidence of an HIV diagnoses (i.e. the year of their first viral load test).

Priority Population
Populations outlined as priorities for HIV programming in Ontario’s response to HIV, including gay, bisexual and other men who have sex with men, including trans men (GBMSM); people who are African, Caribbean or Black (ACB); Indigenous Peoples; people who use injection drugs (PWID); and women. Information from the test requisition (both new and old test requisition forms) and LEP forms are used to assign an HIV diagnosis (i.e. HIV-positive test) to a priority population, where applicable. Unlike the categories traditionally used to describe new diagnoses (known as exposure categories), these priority populations are not mutually exclusive. That means that an HIV diagnosis can be assigned to more than one priority population (if applicable) – an approach which better represents Ontario’s HIV epidemic. To be assigned to any priority population, only information on that single priority population is required. For example, if race/ethnicity is missing but exposure category indicates male-to-male sexual contact, the individual could be assigned the GBMSM priority population. Assignment of priority population is excluded if data is not reported to define that priority population. See Priority populations for more information.

Public health unit

A health agency that provides health promotion and disease prevention programs. There are 34 public health units in Ontario and each has its own unique geographical boundary. See Health regions for more information.

Submitter type

Each HIV test submitter type is a category defined by specific criteria and each HIV test is assigned an HIV test submitter type based on information about the submitter of the HIV test to the Public Health Ontario (PHO) Laboratory. When more than one submitter type is identified for a single HIV test, a hierarchy is used to assign an HIV test to a single submitter type. Therefore, the HIV test submitter types are mutually exclusive. This hierarchy, and the defining criteria for each submitter type, are described under “HIV test submitter types” within the Appendices of « HIV testing in Ontario, 2019 ».

Test requisition form
A form filled out by a health care provider along with each HIV diagnostic test. The HIV diagnostic test requisition form collects information on the age, sex and HIV risk factors of the person getting tested. As of 2018, the HIV test requisition form also collects information on race/ethnicity, country of birth, transgender identity and PrEP status. Note, race/ethnicity and country of birth information has been collected on the Laboratory Enhancement Program (LEP) form since 2009.

Test type

There are three main test types as defined by the type of identifier collected on the test requisition form. HIV tests can be conducted under a patient’s name (nominal), a code assigned by a healthcare provider or a unique anonymous number. Coded and anonymous testing are both forms of non-nominal testing.

Testing rate per 1,000 people

Refers to the number of HIV tests per 1,000 people in Ontario. While the number of tests is influenced by the size of the underlying population (e.g. greater population = greater number of tests), rates take population size into account and remove it as a possible explanatory factor for any observed differences over time or between populations.

Importantly, OHESI uses the number of HIV tests in Ontario to calculate testing rates. It does NOT use the number of unique individuals tested. This means trends may reflect changes in both the number of times an individual gets tested in a year as well as the total number of unique people who get tested.

Women* / Women
Women* is the official priority population as outlined in Ontario’s Provincial HIV/AIDS Strategy; it includes ACB women, women who use injection drugs, Indigenous women, transgender women, other women who face systemic and social inequities, and women who are more likely to be exposed to HIV through a sexual or drug using partner. As indicators of systemic and social inequities of HIV are not available in the HIV surveillance data, the priority population Women* is unable to be defined. Instead, OHESI uses “Women”, which is defined by having ‘Female’ or ‘Trans female’ sex reported. See Priority populations for more information.