evaluation of hepatitis c viral load quantification on dbs in vietnam

Conditions: Hepatitis C; Dried Blood Spot

Summary: in vietnam, the prevalence of hepatitis c virus (hcv) infection is estimated between 0.4% and 5%, which is much higher than the prevalence in europe or in the usa. after hcv diagnosis, hcv viral load quantification is crucial in order to distinguish recovered from active (on-going) hcv infection and hence identify those who need antiviral treatment to cure hcv infection. hcv viral load quantification is also important to assess treatment efficacy. currently, anti-hcv antibodies detection is available around the country. however, access to confirmation of hcv viremia remains scarce particularly in decentralized areas. one of the reason is the limited number of laboratories able to perform this complex biological measurement; moreover, these laboratories are situated only in large urban centres. blood sampling using dbs could help overcome this difficulty of access to a laboratory, and widen access to hcv viral load monitoring. the present movida hep study aims at validating the use of dbs to measure hcv viral load as compared to plasma (gold standard). a secondary objective is to evaluate the measurement of hcv core antigen on dbs. for this, 315 patients need to be enrolled form outpatient clinics in hanoi. the laboratory in charge of these measurements would be the virology laboratory of the national institute of hygiene and epidemiology (nihe) in hanoi (vietnam).

the "monitoring of viral load in decentralised area" (movida) project aims at giving access to viral load (vl) monitoring to the patients coming from remote areas using dried blood spot as tool of sampling. in resource-limited settings, many biological exams are not accessible to the entire population due to logistic and financial constraints. regarding infection with hepatitis b and c viruses (hbv and hcv), serological screening tests are easy to perform and are available nationwide in either laboratory format or rapid diagnosis tests. however, hepatitis b dna and c rna assessment is not available in decentralised area as no laboratory is able to perform this complex biological measurement. who, in their latest guidelines, recommends using dried blood spots (dbs) as an alternative to serum or plasma. blood is easy to collect on dbs, either after veni- or capillary puncture. capillary blood collection can be of great interest when venipuncture is complex, for example in injecting drug users (idus) in whom finding an accessible vein can be difficult. then it is easily transferred, and at a low cost as it does not require a cold chain, to a laboratory able to perform the hcv vl quantification. as of today, little is known about the performance of standard commercial hcv diagnostic assays when using dbs and none of these studies were performed in routine setting in resource-limited setting. in vietnam, hcv seroprevalence in the general population is estimated between 0.4% and 5%, which is much higher than the prevalence in europe or in the us. genotype 1 is the more prevalent in vietnam, genotype 6 that is only found in south east asia is the second most frequent, but other genotypes are circulating . in vietnam, hcv prevalence is much higher in the hiv-infected population and in injecting drug users (idus). currently, anti-hcv antibodies detection is available around the country even if some difficulties remain. however, access to hcv hcv viral load measurement in routine remains scarce particularly in decentralized areas because the technique is complex, expensive and need well-trained personnel and high standard of equipment. thus, hcv viral load measurement remains non accessible to the vast majority of patients diagnosed with hcv. this study (movida hep) aims at evaluating the quality of hcv vl monitoring when using dbs (collection of venous and capillary blood) as compared to plasma (gold standard), in routine condition and using the existing machines. this, to find out if dbs can be used for hcv viremia confirmation in vietnam, in the virology laboratory of the national institute of hygiene and epidemiology (nihe) in hanoi (vietnam) where these measurements would be performed.

Eligibility criteria:
inclusion criteria: * ≥18 years of age * known hcv infection * willing to participate to the study by giving his/her consent. exclusion criteria: none

Keywords: hcv viral load, dried blood spot, hcv core ag