Small Volume Blood Testing Validity and Acceptability for HIV-1 and Hepatitis B (TINIES for BBVs)

Covid-19 has accelerated the move towards increased use of remote healthcare\[4\]. This model is well-suited to people living with chronic blood borne virus (BBV) infections, as they are often asymptomatic and need only routine monitoring to assess for disease progression, response to treatment and medication adverse effects\[5, 6\]. However, routine blood tests still require the patient to attend the hospital for venepuncture to collect several 6 millilitre (ml) tubes twice a year. The Covid-19 pandemic led to a decrease in routine blood monitoring for HIV and HBV, due to a combination of the patient and clinician attempting to reduce hospital exposure\[2, 7\]. This may have a negative impact on patient care due to missed drug toxicity or changes in viral load necessitating drug initiation or changes. Given the post covid-19 shift to remote healthcare for routine appointments is likely to continue in the NHS\[1\], a mechanism of remote blood monitoring would be beneficial to patients and clinicians. Screening for syphilis, hepatitis and HIV using home testing with small volume finger prick blood samples has become established in sexual health services \[8, 9\]. Despite this, home-test finger prick blood sampling use in routine monitoring for patients living with HIV and HBV has not been explored. Finger prick dried blood spots have been investigated as a method of collection for measuring HIV and HBV viral load, particularly in resource-limited settings\[10-13\]. However, the use of dried blood spots for routine monitoring in high-income setting outpatient clinics is limited by reduced sensitivity in detecting low viral loads, and reduced ability to measure other routine blood tests, including haematology and biochemistry. There are few published studies investigating HIV-1 viral load measurement on finger prick blood collected in microcontainers, and none investigating HBV viral load. Studies have found self-taken home HIV tests are acceptable to service-users and increase the uptake of HIV testing in key populations, such as MSM and trans people. In contrast, in a London black African community, TINIES for HIV screening were unpopular and it was unfeasible to scale up their use within primary care\[16, 17\]. Online posting of tests to be self-taken in the home environment is becoming highly acceptable to service users, while recognising this may lead to reduced uptake in certain vulnerable groups\[18\]. Apart from enabling ongoing monitoring in the event of a future lockdown, there are other reasons why remote testing may be beneficial in clinical care of people living with BBV. Testing at home will reduce the burden of hospital visits for otherwise healthy people, reducing time off work for appointments and travel costs. There may also be a cost reduction for both the UK Health Service (NHS), for example by reducing venepuncture appointments. Stigma of attending the hospital may reduce uptake of regular blood monitoring, and remote testing may overcome this barrier.