New specimen types for hepatitis testing may help increase the ease and the extent of screening efforts and epidemiologic studies. Two new specimen types being proposed are dried blood spots and oral fluids.
Dried Blood Spot Specimens
Dried blood spot (DBS) specimens are being investigated for use in hepatitis immunoassays and molecular assays (NAAT). DBS uses a drop of blood from the patient applied to a paper card and allowed to dry. The card can then be taken or mailed to a laboratory where it is eluted and used for testing.
The advantage of DBS specimens is that specimens can be collected without the need of a trained phlebotomist and can be easily and cheaply shipped through the mail. A patient could even self-collect, avoiding an office visit and allowing patients in remote settings to still have access to testing.
Assays using saliva for HBsAg and HCV are now available. While not yet in widespread use, if they are found to be accurate, oral fluid test devices could increase access to testing in hard-to-reach populations. These would be screening tests that still required follow-up for confirmation (using NAAT in the case of HCV and other HBV serology tests in the case of a positive HBsAg that would aid in HBV diagnosis).