Concept: Human Immunodeficiency Virus (HIV) - Method of Identification

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Concept Description

Last Updated: 2013-07-17

Introduction
    This concept provides a working definition of Human Immunodeficiency Virus (HIV) and describes the methods used at MCHP to investigate HIV in the administrative data held in the Manitoba Population Research Data Repository. The concept lists the ICD-9-CM and ICD-10-CA diagnostic codes to identify HIV in the hospital abstracts data and the medical services data, and lists the codes that are used in laboratory tests to investigate its presence in the population. SAS code (internal access only) is also available for working with the laboratory data.
Definition of Human Immunodeficiency Virus (HIV)
MCHP HIV Algorithms
    The following two methods have been used at MCHP to determine testing and to identify individuals with HIV.
1. Brownell et al. (2012)
    In Brownell et al. (2012), a Manitoba Health report on the provincial count of new cases of HIV by age and sex distribution between 2000 and 2009 was examined (Manitoba Health - Public Health and Primary Health Care Division, 2010). For youths aged 15 to 19 years, 23 cases of HIV for females were identified and six for males. For youths less than 15 years of age, there were seven new cases for females and one case for males. According to this provincial report, between 2000 and 2009, the incident of new cases of HIV was four times greater for female youths. In 2010, there were two new cases of HIV for females aged 15 to 19 years of age and one for males. For those less than 15, only one new case was identified in females and none for males.

    Because the percent of youths with a reported case of HIV in Manitoba is relatively low, it precludes presentation by region or income quintile. For more information read the section HIV in Brownell et al. (2012) .
2. Lix et al. (2012)
    In Lix et al. (2012), the Cadham Provincial Laboratory (CPL) data from 1992/93 to 2008/09 was used to identify the frequency of records for HIV tests with a linkable PHIN; that is, a PHIN that can link the CPL data to the administrative records at the MCHP Population Health Repository. Prior to 2006/07, the PHINs in the CPL data were not linkable to the administrative data. In 2006/07, only a small amount of tests were linkable and this number increased significantly in 2007/08 and in 2008/09. Thus, record linkage is not possible prior to 2007/08 in Manitoba.

    Data from the CPL Serology Section was used to identify the CPL number of tests and the frequency of positive laboratory-confirmed cases in Manitoba. As an initial screening test, CPL uses an ELISA (enzyme-linked immunosorbent assay) on serum to detect antibodies for HIV and all positive ELISA test results are confirmed by a western blot (Manitoba Health - Communicable Disease Control Branch, 2010). In Manitoba, CPL is responsible for all confirmatory HIV antibody testing.

    Table 1 reports the AUXCD5 codes used to identify HIV in the Serology Section of CPL. For more information on CPL, see the CADHAM Provincial Laboratory (CPL) - Overview of Services and Data concept.

    NOTE: Individuals infected with HIV usually develop detectable antibodies within two weeks to three months after initial infection (antibodies detected by ELISA and western blot). However for some, this detection window might be more prolonged (Manitoba Health - Communicable Disease Control Branch, 2010).
Table 1 - HIV: Serology Section
    STARTDT 1 STOPDT 2 AUXCD5 DESCR40
    11/25/1993 01/01/2099 HIV ANTI-HIV1/HIV2
    01/01/1990 05/01/2006 HIV1C HIV1 CONFIRM
    01/01/1990 05/01/2006 HIV2C HIV2 CONFIRM
    10/23/2007 01/01/2099 HIVA ANTI-HIV1/HIV2
    01/01/1990 01/01/2099 HIVAG HIV1 ANTIGEN DETECTION
    04/02/1998 01/01/2099 HIVDN HIV-DNA
    04/30/2003 01/01/2099 HIVGT HIV-1 DRUG RESISTANCE
    01/01/1990 05/01/2006 HIVIF HIV1 IFA
    12/21/2006 01/01/2099 HIVN ANTI-HIV1/HIV2
    09/24/1996 01/01/2099 HIVQR HIV QUANTITATIVE RNA - PCR
    02/01/2008 01/01/2099 HIVRT ANTIBODY TO HIV (RAPID TEST)
    05/01/2006 01/01/2099 HIVVL HIV VIRAL LOAD
    01/01/1990 01/01/2099 HVCC HIV1/HIV2 CROSSREACT/CONFIRM
    05/07/2009 01/01/2099 HVCOM COMBO ANTI-HIV-1/O/2 AND HIV-1 P24
    01/01/1990 12/03/1993 HVCS HIV1/HIV2 SCREEN
    05/03/1993 05/01/2006 HVCS2 HIV1-HIV2 SUPPLEMENTARY SCREEN TEST
    03/20/1997 05/01/2006 HVRNA HIV QUANTITATIVE RNA-PCR
    12/21/2006 01/01/2099 ROHIV ANTI-HIV1/HIV2

    1 - The date that the code was created in the file.
    2 - The date that the code became inactive.
Comparison of Lab Data to Hospital Discharge Abstracts and Medical Services Data
    Incident HIV cases identified from the hospital abstracts data and medical services data were compared to the CPL data for the fiscal years 2007/08 and 2008/09. ICD-9-CM codes 042 and ICD-10-CA codes B20-B24 were used to identify the diagnoses of HIV. In the two-year period, a total of 203 new cases of HIV were identified in the hospital abstracts and medical services/physician claims data. Of these cases, 33.0% had a positive HIV test result in the CPL data 30 days before or after the diagnosis date. When a 180-day period was used, 45.8% had a positive test in the CPL data, indicating a moderate agreement between positive test results and diagnoses for HIV in hospital abstracts and medical services/physician claims data. For more information on how HIV was investigated in the CPL data, read the section titled Case Study #1: Record Linkage for HIV Tests in Lix et al. (2012).
SAS Code
    SAS code for identifying HIV tests in the Cadham Provincial Laboratory data is available in the SAS code and formats section below (internal access only).
Limitations / Cautions
  • CPL performs all clinical serologic confirmatory testing for HIV in Manitoba, but laboratory data may not capture all cases in a jurisdiction.

  • The number of incident cases and general trends of HIV within the population should be construed with caution due to an under-diagnosis of cases, underreporting, incomplete reporting of anonymous testing, and the possibility of dual reporting (under nominal and non-nominal testing) (Manitoba Health - Communicable Disease Control Branch, 2010).

  • A value of P [Positive] to identify a positive test result in the POSNEG field [Positive-Negative] for specific AUXCD5 codes in the CPL data was used to determine a positive test result.

  • The AUXCD5 codes used to identify HIV in the Serology Section should be verified at the beginning of each new study to ensure they are up-to-date.

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References 

  • Brownell M, Chartier M, Santos R, Ekuma O, Au W, Sarkar J, MacWilliam L, Burland E, Koseva I, Guenette W. How are Manitoba's Children Doing? Winnipeg, MB: Manitoba Centre for Health Policy, 2012. [Summary] [Full Report] [Data extras] [Errata] (View)
  • Fransoo R, Mahar A, The Need to Know Team, Anderson A, Prior H, Koseva I, McCulloch S, Jarmasz J, Burchill S. The 2019 RHA Indicators Atlas. Winnipeg, MB: Manitoba Centre for Health Policy, 2019. [Summary] [Full Report] [Data extras] [Errata] (View)
  • Lix L, Smith M, Azimaee M, Dahl M, Nicol P, Burchill C, Burland E, Goh C, Schultz J, Bailly A. A Systematic Investigation of Manitoba's Provincial Laboratory Data. Winnipeg, MB: Manitoba Centre for Health Policy, 2012. [Summary] [Full Report] (View)
  • Manitoba Health (2010). Communicable Disease Control Branch. Communicable Disease Management Protocol - Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome. Available on-line at:http://www.gov.mb.ca/health/publichealth/cdc/protocol/hiv.pdf. Accessed May 1st, 2013. .(View)
  • Manitoba Health (2010). Public Health and Primary Health Care Division. Manitoba Health statistical update: HIV and AIDS. Available at: http://www.gov.mb.ca/health/publichealth/surveillance/hivaids/dec2010.pdf. Accessed May 1st, 2013 .(View)