Hepatitis C laboratory and diagnostic testing: iphis data entry scenarios

Transcription

1 QUICK REFERENCE GUIDE Hepatitis C laboratory and diagnostic testing: iphis data entry scenarios Introduction This guide has been extracted from the hepatitis C iphis User Guide to assist users with appropriate data entry, based on the updated hepatitis C case definition in the Ontario Public Health Standards Infectious Diseases Protocol, Appendix B. The iphis data entry scenarios outlined below apply to cases reported on or after January 1, For cases reported before that time, no changes to the aetiological agent field in iphis should be made. Any additional laboratory information received after January 1, 2018 should only be entered into the Laboratory section in iphis. The iphis data entry for the scenarios listed below are guided by the following: CHANGES TO THE AETIOLOGIC AGENT FIELD: Infection status will remain classified as identified by the first RNA report to the public health unit (PHU) as long as it is collected within the first six months of the positive anti-hcv antibody. Previous negative anti-hcv antibody results received at any time can result in the case classification being updated to Newly Acquired if the negative result was within 2 years of the positive anti-hcv antibody as identified in the Hepatitis C Appendix B case definition. INCONCLUSIVE ANTI-HCV OR LOW RNA RESULTS: Inconclusive anti-hcv antibody results are considered negative for hepatitis C, unless the concurrent RNA is positive, in which case the inconclusive anti-hcv antibody result is considered positive for hepatitis C. RNA result <15 IU per ml are considered RNA positive. RNA results of <15 IU per ml will be reported as Inconclusive if anti-hcv antibody is negative. RNA result of <15 IU per ml will be reported as Low-detect if the anti-hcv antibody is positive.

2 DEFINITION OF RNA CLEARANCE: Cleared spontaneously (without treatment): testing HCV RNA negative at 6 months or more after acquisition. Acquisition is determined in consideration of risk factors, symptoms and previous test results if available. Cleared after treatment (i.e. Sustained Virologic Response (SVR)): Absence of detectable HCV RNA on all available specimens taken at least 12 weeks after treatment completion. Create a new case in someone who was a previous case if: Evidence of RNA clearance (spontaneously or after treatment) and then subsequently RNA is positive again. Individual infected with one genotype, subsequently becomes infected with an additional genotype (while not on treatment). Note that if an additional genotype appears while case is on treatment, this may be indicative of genotype suppression that is no longer being suppressed due to treatment and not a new infection; a new case should not be created. Quick Reference Guide: Hepatitis C laboratory and diagnostic testing iphis data entry scenarios 2

3 The following tables provide some potential scenarios that public health units may encounter and some proposed data entry recommendations for case reported to public health units on or after January 1, Table 1. Multiple RNA results Multiple RNA positive results Enter first result in laboratory section; enter subsequent results in laboratory section under health unit discretion. Enter first result in laboratory section; and Multiple RNA negative results Enter in laboratory section all RNA negative results until all have been negative for at least 12 weeks after treatment completion OR enter in laboratory section all RNA results within 6 months after first anti-hcv antibody positive and at least 6 months from last positive RNA if not being treated. Enter all other results in laboratory section under health unit discretion. Conversions from RNA positive to RNA negative within or after 6 months Conversion from RNA positive to RNA negative to RNA positive again all within 6 months Conversion from RNA positive to RNA negative 6 months or more apart and then Do not change Aetiological Agent field; remains classified in iphis as infectious; enter RNA negative result in laboratory section. This is recommended because it is important to track the RNA status from when the case was reported to the health unit. If RNA negative occurs with treatment, and all available RNA tests are negative at least 12 weeks after treatment ends, and then converts to RNA positive again, create new case. If RNA negative occurs spontaneously without treatment, do not change Aetiological Agent field; remains as infectious; enter RNA negative and positive results in laboratory section; do not create a new case. Create new case. Quick Reference Guide: Hepatitis C laboratory and diagnostic testing iphis data entry scenarios 3

4 RNA positive again Table 2. Genotype results Only one case should be created. Individual reported as being co-infected with two genotypes (on same specimen) Select the Multiple Genotypes field in the laboratory section when entering the laboratory result. For multiple genotypes, specify in the Further Differentiation field which genotypes are present. For specimens indicated as cross-reactive, select the dominant subtype. For more details please refer to the hepatitis C iphis user guide section 1.1 Case Details. RNA positive with genotype x followed by RNA positive with genotype y while on treatment If genotype y appears while case is on treatment, this could be indicative of previous genotype suppression that is no longer being suppressed. The laboratory report should be entered into the laboratory section and no new case should be created. Close existing hepatitis C case record. RNA positive with genotype x followed by RNA positive with genotype y while not on treatment Create new case and select the Multiple Genotypes field in the laboratory section when entering the laboratory result. For multiple genotypes, specify in the Further Differentiation field which genotypes are present. Any new information should be reflected in the new case record. However, once RNA negative results are received, both records (original and new) should be updated accordingly. Quick Reference Guide: Hepatitis C laboratory and diagnostic testing iphis data entry scenarios 4

5 Table 3. Historical test results are discovered First RNA result is positive and received within 6 months after anti-hcv antibody positive results First RNA result is negative and is received within 6 months after anti-hcv antibody positive results First RNA result (positive or negative) is received more than 6 months after anti- HCV antibody positive result Anti-HCV antibody positive result with no indication of previous antibody testing; afterwards receive a previous negative anti-hcv antibody result that was within 2 years prior to testing anti-hcv positive Update Aetiologic Agent to indicate RNA positive. Enter results in laboratory section. Update Aetiologic Agent to indicate RNA negative. Enter results in laboratory section. Do not update the Aetiological Agent. Aetiologic agent should remain as Unspecified RNA status. Enter result in laboratory section. Update Aetiologic Agent field to indicate Newly acquired. Table 4. Inconclusive anti-hcv or low RNA results (<15 IU per ml) Anti-HCV antibody positive and RNA results <15 IU per ml This will be reported as RNA Low detect ; treat as RNA positive. Quick Reference Guide: Hepatitis C laboratory and diagnostic testing iphis data entry scenarios 5

6 Anti-HCV antibody negative and RNA results <15 IU per ml First RNA result inconclusive; subsequent results positive First RNA result inconclusive; subsequent results negative Inconclusive anti-hcv antibody results This will be reported as RNA Inconclusive ; treat as RNA positive. RNA inconclusive is treated as RNA positive and would have been entered as RNA positive. Enter subsequent result in laboratory section at the discretion of the health unit. RNA inconclusive is treated as RNA positive and would have been entered as RNA positive. Do not update Aetiological Agent field. Enter subsequent result in laboratory section. PHOL Labstract recommends submitting blood work for RNA testing. If RNA not available, then consider inconclusive HCV antibody results as negative. Table 5. Immunocompromised Individuals Anti-HCV antibody negative and RNA <15 IU per ml (RNA inconclusive) or >15 IU per ml (RNA detected) To identify an individual as newly acquired or previously acquired/unspecified, any available previous RNA results must be considered rather than previous anti-hcv antibody results. Quick Reference Guide: Hepatitis C laboratory and diagnostic testing iphis data entry scenarios 6

7 Disclaimer This document may be freely used without permission for non-commercial purposes only and provided that appropriate credit is given to Public Health Ontario (PHO). No changes and/or modifications may be made to the content without express written permission from PHO. Public Health Ontario acknowledges the financial support of the Ontario Government. Quick Reference Guide: Hepatitis C laboratory and diagnostic testing iphis data entry scenarios