Introduction Delta hepatitis is frequently neglected amongst hepatitis guidelines and publications. There are limited data on the prevalence of delta in the UK and this is likely to be a rapidly evolving area.
Aim The aim was to examine the rate of testing for delta hepatitis amongst all HBsAg (+) patients seen over a 3 year period in the large liver unit at St Mary's Hospital (SMH), London. Clinical characteristics of delta (+) patients were reviewed.
Method All HBsAg (+) results generated from the virology department from Jan 1 2007 to Dec 31 2009 were recorded. Duplicate, indeterminate and untraceable requests were excluded and the number of HBsAg (+) patients that reached hepatology specialist care established. All delta serology requests (ELISA) over the 3 year period were also reviewed. Further trawl of histology and clinical databases was made to identify any delta (+) patients diagnosed prior to 2007. The medical notes of delta (+) patients were reviewed.
Results 858 HbsAg (+) patients were identified that were seen in specialist hepatology clinics in the trust over the 3 years. Of these, only 56 had been tested for delta (6.5%). Delta Ab was (+) in four patients (7.1%). Delta testing was predominantly done in patients with abnormal liver function and low HBV DNA levels. A total of 13 delta (+) patients were found after the subsequent review of virology and histology records from 2000 onwards. Patients were young (mean age 36) with advanced disease (cirrhosis in 55%). The 13 patients were of varied ethnicity, having been born in 10 different countries.
Conclusion The rate of testing for delta was extremely low. The positivity rate was also low but equivalent to the rate reported amongst another London cohort where universal delta testing is undertaken amongst HBsAg (+) patients (Cross et al J Med Virol 2008). If the prevalence of delta is similar between the 2 London centres then 8.5% of the 858 patients at SMH would be expected to be delta (+) equivalent to 73 patients, rather than the four found during the 3 years of study. Prospective universal testing for delta is recommended to determine whether there is significant underdiagnosis occurring.