I Johannessen on behalf of SCVCG:
Approved version 6 March 2013
Scottish Clinical Virology Consultants Group (SCVCG):
Recommendations for Blood-Borne Virus Testing in Haemodialysis Patients
The purpose of this document is to recommend to Scottish clinical virology laboratories an approach to blood-borne virus (BBV) testing of patients undergoing haemodialysis (HD). The overall aim is to support clinical governance and ensure patient safety in Scottish HD units. The recommendations are based on current key guidance (see below) and suggest a minimum standard as well as additional tests that individual diagnostic laboratories may wish to offer to their users. The latter will depend on the local availability of such tests.
General notes:
Haemofiltration (HF) on certain systems (for example, the Aquarius system) does not necessitate BBV testing. Thus, HF is not considered in this document.
It is assumed that low-reactive BBV test results will be assessed in further tests (for example, low-reactive HCV-Ab result in screening assay will be re-tested in a second assay).
Guidance:
‘Good Practice Guidelines for Renal Dialysis/Transplantation Units (Prevention and Control of Blood-borne Virus Infection)’, UK Department of Health, 2002
‘Good Practice Guidelines for Renal Dialysis/Transplantation Units (Prevention and Control of Blood-borne Virus Infection) – Addendum: Guidelines for Dialysis Away from Base (DAFB)’, UK Department of Health, 2010
‘RA Guidelines - Blood Borne Virus Infection’, Renal Association, 2009
Key:
Ab: Antibody
Ag: Antigen
BBV: Blood-borne viruses
DAFB: Dialysis away from base
HD: Haemodialysis
HF: Haemofiltration
HBs: HBV surface antibody
HBV: Hepatitis B virus
HBV-cAb: HBV core antibody
HBV-sAb: HBV surface antibody
HBV-sAg: HBV surface antigen
HCV: Hepatitis C virus
HCV-Ab: HCV antibody
HCV-Ag: HCV antigen
HCV-Ab/Ag: HCV antibody/antigen combination asssay
HD: Haemodialysis
HIV: Human immunodeficiency virus
HIV-Ab: HIV antibody
HIV-Ab/Ag: HIV antibody/antigen combination assay (4th generation)
PCR: Polymerase chain reaction
PD: Peritoneal dialysis
1. BBV Testing Prior to First Time Haemodialysis
The aim is to detect BBV infection prior to HD. Thus, BBV tests should be offered to patients about to embark on HD for the first time. Such tests should be highly sensitive, rapid and offered out-of-hours (unless an agreed local approach entails segregation of a HD machine for a new patient until BBV test results become available first thing the next working day).
Patients should be tested for BBV immediately prior to first time HD unless BBV-negative results have been obtained within 1 month from starting HD (and risk assessment does not give rise to concerns of recent BBV exposure). The tests include HIV-Ab/Ag, HBV-sAg and HCV-Ab. Additional tests include HCV-PCR, HCV-Ab/Ag or HCV-Ag assessments that should be considered if the patient is immunosuppressed or being admitted from a unit where recent HCV transmission has occurred.
The approach outlined below includes renal transplant recipients and peritoneal dialysis patients returning to HD.
Recommended minimum standard:
HBV-sAg
HCV-Ab
HIV-Ab/Ag
Additional tests/alternative testing approaches to consider:
HBV-cAb
Background HBcAb-positive patients will not receive HBV vaccine course.
HCV-PCR, HCV-Ab/Ag or HCV-Ag
Background: Delay of up to 3 months for HCV Ab to develop following HCV infection.
2. BBV Testing during Regular Haemodialysis
The aim is to detect BBV infection during HD. Thus, BBV tests should be offered on a regular basis to patients undergoing HD. The tests include HIV-Ab/Ag, HBV-sAg and HCV-Ab. Additional tests include HCV-PCR, HCV-Ab/Ag or HCV-Ag assessments that should be considered.
Recommended minimum standard:
Every 3 months:
HBV-sAg
HCV-Ab
Annually:
HIV-Ab/Ag
Additional tests/alternative testing approaches to consider:
HBsAg monthly
Background: High risk of HBV transmission to other patients in a HD unit from a patient with active HBV infection.
HBsAg every 12 months in HBV vaccine responders (anti-HBs ³10 mIU/ml)
Background: Protective HBV immunity obtained through successful vaccination reduces need for more frequent HBV-sAg tests.
HCV-PCR, HCV-Ab/Ag or HCV-Ag every 3, 6 or 12 months
Background: Delay of up to 3 months for HCV Ab to develop following HCV infection.
HIV-Ab/Ag every 3, 6 or 12 months
Background: Non-discriminatory general approach that does not rely on repeat risk assessments.
3. BBV Testing Prior to Dialysis Away From Base
The aim is to provide the destination dialysis unit (whether within or out with the UK) current BBV test results to ensure appropriate HD approach when patients undergo dialysis away from base (DAFB). The tests include HIV-Ab/Ag, HBV-sAg and HCV-Ab. Additional tests include HCV-PCR, HCV-Ab/Ag or HCV-Ag assessments that should be considered.
Recommended minimum standard:
HBV-sAg
HCV-Ab
HIV-Ab/Ag
Additional tests/alternative testing approaches to consider:
HBV-sAb
Background: Destination unit may request such test results as evidence of successful HBV vaccination (that may affect frequency of their HBV-sAg tests).
HBV-PCR
Background: Destination unit may request such test results to ensure no evidence of active HBV infection (for example, in the absence of evidence of successful HBV vaccination).
HCV-PCR, HCV-Ab/Ag or HCV-Ag
Background: Destination unit may request such test results to ensure no evidence of active HCV infection.
4. BBV Testing Following Return from Dialysis Away From Base
The aim is to ensure detection of BBV infection during DAFB prior to HD in the main area of the home unit. The tests include HIV-Ab/Ag, HBV-sAg and HCV-Ab. Additional tests include HCV-PCR, HCV-Ab/Ag or HCV-Ag assessments that should be considered. The approach at the home unit will vary according to risk of BBV transmission during DAFB. Risk assessment should be performed to gauge BBV risk, which takes into account BBV prevalence in the geographical region where DAFB was carried out. A broad outline of risk is given in current guidance as outlined below. (Note that there is no UK database of the world’s HD units.)
- LOW RISK AREA
For example, UK, Europe (some destinations may be considered intermediate risk), USA, Canada, Australia, New Zealand and Japan
Does not require segregation of HD machine.
Individual cases should be assessed in terms of suspension from transplant list.
Recommended minimum standard (low risk):
HBV-sAg
HCV-Ab
HIV Ab/Ag
Additional tests/alternative testing approaches to consider:
HCV-PCR, HCV-Ab/Ag or HCV-Ag
Background: Delay of up to 3 months for HCV Ab to develop following HCV infection.
- MODERATE/HIGH RISK AREA
Moderate risk: For example, South East Asia, South America, Middle East
Does not require segregation of HD machine once initial (upon return) BBV test results are shown to be negative.
Suspension from transplant list until initial (upon return) BBV test results are shown to be negative.
High risk: For example, Indian subcontinent and parts of Africa
Requires segregation of HD machine.
Suspension from transplant list until end of 2 months period (see below).
Recommended minimum standard (moderate/high risk):
Every 2 weeks for first 2 months:
HBV-sAg
HCV-PCR
Additional tests/alternative testing approaches to consider:
HCV-Ab/Ag or HCV-Ag (instead of, or in addition to, HCV-PCR)
Background: To cut down turn-around time and cost of HCV testing.
Fortnightly BBV testing for first 3 months
Background: To ensure detection of very recent BBV infection whilst undergoing DAFB.
HIV-Ag/Ab at end of 3 months period
Background: Non-discriminatory general approach that does not rely on repeat risk assessments.
5. HBV vaccination
Patients undergoing HD should receive a HBV vaccine course. This will usually involve a regimen of 4 doses administered intra-muscularly (intra-dermally if expertise is available) at 0, 1, 2 and 6 months using a high concentration vaccine (for example, Engerix B 40ug). An anti-HBs assessment should be carried out 1-2 months after administration of the last dose. If levels are ³100 mIU/ml, the individual is considered a responder and will not require further doses. If levels are 10-100 mIU/ml, the individual is considered a low responder and will require a further dose. If levels are <10 mIU/ml, the individual is considered not to have responded to vaccination and should be offered a repeat primary course. If the anti-HBs result at the end of a repeat primary course is still <10 mIU/ml, the patient should be considered a non-responder and no further doses offered. For responders, an annual anti-HBs test should be carried out followed by a booster dose if levels have fallen to <10 mIU/ml.
If exposure to HBV occurs, all HD patients should be offered a vaccine booster. Also, a booster should be considered for patients about to visit a region of high HBV prevalence (particularly if they have not received a booster within the last 12 months).
The role of HBV-cAb testing is uncertain as a result of the low prevalence of HBV infection in the UK. Whilst some units use a positive result (together with a negative HBV-sAg result) to guide the need for HBV vaccination, it is costly to add the test to a routine Scottish regime and the benefit is questionable.
Additional tests/alternative testing approaches to consider:
Vaccine responders receive annual booster without anti-HBs testing
Background: Unclear value of annual anti-HBs testing to guide administration of annual HBV vaccine booster doses.
6. Recommendations for a Minimum Standard
The recommendations above recognise both direct and indirect consequences of BBV transmission in a HD unit: direct impact on patients’ health as well as loss of faith in the service provided and medico-legal implications for health boards. Thus, the approach above (summarised below) is a cautious one that puts patient safety at its centre. It is also a simple ‘catch all’ approach that is conducive to support busy renal HD units.
- BBV Testing Prior to First Time Haemodialysis
HBV-sAg
HCV-Ab
HIV-Ab/Ag
- BBV Testing during Regular Haemodialysis
Every 3 months:
HBV-sAg
HCV-Ab
Annually:
HIV-Ab/Ag
- BBV Testing Prior to Dialysis Away From Base
HBV-sAg
HCV-Ab
HIV-Ab/Ag
- BBV Testing Following Return from Dialysis Away From Base
- LOW RISK AREA
HBV-sAg
HCV-Ab
HIV Ab/Ag
- MODERATE/HIGH RISK AREA
Every 2 weeks for first 3 months:
HBV-sAg
HCV-PCR
At end of 3 months’ period:
HBV-sAg
HCV Ab
HCV-PCR
HIV-Ab/Ag
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