HDV antibody (IgM)
Liver Pathology Overview / Directory
Purpose of the test
In acute HBV/HDV coinfection, IgM antibody to HDV is raised a few days to a few weeks after the onset of symptoms and seroconversion to IgG anti-HD occurs later. As IgM anti-HD is the earliest antibody to appear and often the sole marker present during the clinical stage, it represents the test of choice for the identification of HBV/HDV coinfection in acute HBsAg-positive hepatitis. Serial testing over several weeks optimises the probability of correct diagnosis, but a reasonable compromise is a first test at the onset of symptoms, followed by a second test 14 days later. This double testing identifies 35 to 50% more HBV/HDV coinfection over single testing.
As a rule, the antibody response to superinfection is more rapid and brisk than in coinfection. IgM anti-HD is present at or soon after the onset of symptoms, followed shortly by the IgG antibody; the IgM anti-HD pattern is therefore helpful to distinguish coinfection from superinfection.
More important, whereas Ig G anti-HD usually persists, IgM anti-HD declines rapidly in hepatitis D that resolves, but increases to high titres in HDV infections that progress, thus, monitoring for IgM anti-HD provides helpful information on the course and prognosis of Hepatitis D, the persistence of IgM antibody indicating that hepatitis D is becoming chronic. In fact, the presence and titre of IgM anti-HD correlate directly with the replication of HDV and with the inflammatory activity of the underlying liver disease. HDV antibody (IgM) test can be used in conjunction with HDV antibody (IgG) and HDV RNA in the management of HDV acute and chronic infection.
Reference Range
Negative and positive
Sample Requirements
200 ul Serum or 4 – 5 ml clotted blood
Storage and Transport
Store whole blood at 2 – 25°C for no longer than 48 hours. Separate serum from whole blood within 48 hours of collection. Serum or specimens may be stored at 2 – 8°C for up to 5 days or frozen at – 20°C or colder.
Whole blood must be transported at 2 – 25°C and processed within 48 hours collection. Serum may be transported at room temperature or 2 – 8°C.
Samples sent by post or by courier must be appropriately labelled and packaged in leak-proof plastic containers in accordance with Post Office regulations. Frozen sera must be similarly packaged and shipped in dry ice. All costs must be met by the sender.
Turnaround Time
10-14 working days
5 - 10 days for urgent samples
Factors affecting results or interpretation
(i) Bacterial contamination, repeated freeze-thaw cycles or heat inactivation of the specimens may affect the absorbance values of the samples with consequent alteration of anti-HD levels.
(ii) Diagnosis of an infectious disease should not be established on the basis of a single test result. A precise diagnosis, in fact, should take into consideration the patient’s clinical history, symptomatology, as well as serological data
(iii) Reliable results are dependent on adequate specimen collection, transport and storage.
(iv) Failure to separate whole blood within 6 hours collection.
(v) Failure to label specimen with patient name, date of birth and precise identifier
(vi) Failure to fill in a consultation-request form, in particular clinical information and doctor to be notified of findings.
Price
Price available on application - please contact adrian.turner@kch.nhs.uk. Discounts could be available for significant workloads.
Contacts
Dr. Dazhuang Shang, Principal Clinical Scientist/Service Manager T 020 3299 3732 or x2239
References
http://referrals.kch.nhs.uk/directory/liver/liver-pathology/hepatitis-testing-hts/
