Risk Of Hcv Infection In Recipients Of Blood Transfusion
Prior to 1992, blood transfusions carried a high risk of HCV infection, approximately 15-20% with each unit transfused. In 1988, 90% of cases of posttransfusion hepatitis were due to NANBH viruses which was later found out to be due to HCV. The move to all-volunteer blood donors instead of paid donors had significantly reduced the risk of posttransfusion hepatitis to 10%. Screening of blood further reduced the rate of posttransfusion hepatitis C by a factor of about 10,000 to a current rate of 1 per million transfusions. The few cases that still occur are due to newly infected people donating blood before they have developed antibodies to the virus, which can take up to 6-8 weeks.
What To Expect During Testing
A healthcare provider will take a blood sample for analysis.
The needle may sting a little as it enters your skin, and you may have a bruise on the site of the draw for a few days.
Results are usually available within a few days or a few weeks at most.
The HCV RNA PCR test is conducted through a process called polymerase chain reaction . There are two approaches to this process: qualitative and quantitative.
Hepatitis C Antibody Blood Test With Reflex On Positives
Assess exposure to hepatitis C virus infection and tests blood safety.
Also Known As: HCV, Hep C.
Preparation: No fasting required. Stop biotin consumption at least 72 hours prior to the collection.
Test Results: 2-3 days. May take longer based on weather, holiday or lab delays.
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Blood Transfusion Issues And Donor Counseling
Guidelines for donor notification for donors positive for transfusion transmissible infections are outlined in An Action Plan for Blood Safety by National AIDS Control Organization 2004. A blood donor is offered an option to know his TTI status at the time of registration for blood donation after due counseling and give consent for the same.
Notifying donors regarding a single positive screening test is fraught with the risk of causing undue anxiety and stress to a donor. If a screening test is positive, the blood unit should be immediately discarded. Presently there are no guidelines regarding confirming the test results before informing the donor. In case of samples with low S/CO and grey zone samples, a retesting of the donor samples using a different assay would be imperative before notifying the donor. There are clear cut guidelines regarding donor notification and referral for HIV positive blood donors with integrated counseling and testing centers available for the same. Donors who are positive for viral hepatitis markers have to be counseled by blood bank staff. An algorithm for donor counseling for HCV positive donors is outlined in .
Algorithm for donor counseling for HCV positive donors
Can I Take The Test At Home
At-home hepatitis C tests are available that allow patients to collect a blood sample at home and mail it to a laboratory for testing. Test samples are collected through pricking a finger with a sharp object, called a lancet, thats included in the test kit.
At-home HCV testing is a form of hepatitis C antibody testing and does not test for hepatitis C RNA or the strains genotype. Testing for hepatitis C at home is not a substitute for testing performed by a health care professional, and positive test results may need to be confirmed by laboratory-based testing.
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Question 5 How Do You Interpret Hcv Antibody Reactive And Hcv Rna Not
A reactive HCV antibody test result combined with a not-detected HCV RNA result indicates no laboratory evidence of a current active HCV infection no further action is required in most cases.
If distinction between a true positive and a biologic false-positive result for HCV antibody is desired, the CDC suggests that one can consider testing with another HCV antibody assay. If there is concern regarding the handling or storage of the test specimen, obtain a new sample for repeat testing.6
Hepatitis C Antibody With Reflex To Pcr
- Hepatitis C Ab w/RFLX PCR
- Lab Code
- Hepatitis C Antibody w/Reflex PCR
The Qualitative detection of Hepatitis C virus IgG and IgM antibodies in human sera by the FDA approved Abbott ARCHITECT Anti-HCV test two-step chemiluminescent immunoassay.
In the first step, sample, assay diluent, and recombinant HCV antigen coated paramagnetic microparticles are combined. Anti-HCV present in the sample binds to the rHCV coated microparticles. In the second step, anti-human IgG/IgM acridinium-labeled conjugate is added, which binds to IgG and IgM anti-HCV. Then pre-trigger and trigger solutions are added to the reaction mixture. The resulting chemiluminescent reaction is measured as relative light units .
The presence or absence of IgG/IgM anti-HCV in the sample is determined by comparing the chemiluminescent signal in the reaction to the cutoff signal determined from an ARCHITECT Anti-HCV calibration. Specimens with signal to cutoff values 1.00 are considered reactive for IgG/IgM anti-HCV. Specimens with S/CO values < 0.79 are considered nonreactive and specimens with S/CO values between 0.80 and 0.99 are Indeterminate.
Reactive anti-HCV will reflex to Hepatitis C RNA, Quantitative for confirmation with an additional charge.
For anti-HCV testing without PCR reflex for REACTIVE results, see Hepatitis C Antibody without PCR reflex on reactive samples .
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Discusses Physiology Pathophysiology And General Clinical Aspects As They Relate To A Laboratory Test
Hepatitis C virus is recognized as the cause of most cases of posttransfusion hepatitis and is a significant cause of morbidity and mortality worldwide. In the United States, HCV infection is quite common, with an estimated 2.4 million chronic HCV carriers.
Laboratory testing for HCV infection usually begins by screening for the presence of HCV antibodies in serum, using an FDA-approved screening test. Specimens that are repeatedly reactive by screening tests should be confirmed with HCV tests with higher specificity, such as direct detection of HCV RNA by reverse transcription-PCR or HCV-specific antibody confirmatory tests.
HCV antibodies are usually not detectable during the first 2 months following infection, but they are usually detectable by the late convalescent stage of infection. These antibodies do not neutralize the virus and they do not provide immunity against this viral infection. Decrease in the HCV antibody level in serum may occur after resolution of infection.
Current screening serologic tests to detect antibodies to HCV include enzyme immunoassay and chemiluminescence immunoassay . Despite the value of serologic tests to screen for HCV infection, several limitations of serologic testing exist:
-There may be a long delay between exposure to the virus and the development of a detectable HCV antibody
-False-reactive screening test result can occur
-A reactive screening test result does not distinguish between past and present HCV infection
Hepatitis C Reflex Testing
To ensure complete and timely diagnosis of HCV, HCV reflex testing is recommended following a reactive hepatitis C antibody screening test. Reflex testing means the laboratory will perform the hepatitis C antibody test, and if the result is positive, the laboratory will immediately perform an HCV RNA test on the same specimen. If the subsequent HCV RNA test is negative, HCV infection is effectively ruled out for most patients. If the reflex HCV RNA test is positive, a diagnosis of active HCV infection has been confirmed, and the individual should be referred directly for HCV care and treatment.
Reflex testing obviates the need for the patient to return for follow-up testing should the initially HCV antibody test be reactive. If the RNA test is negative, the work-up is done, and the patient may be reassured.
- Rationale for reflex testing:
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Question 2 For Whom Is Hcv Screening Recommended
The US Preventive Services Task Force and the CDC recommend 1-time screening for HCV infection for adults born 1945 through 1965.2,3 One-time screening is also recommended for adults with high risk due to:
- Injection drug use 3,4
- Receipt of transfusions or organ transplants prior to July 19923,4
- Having ever received long-term hemodialysis3,4
- Receipt of clotting factor concentrates produced before 19873,4
- HIV infection the co-infection rate among this group is 20% to 30%5
Screening is also recommended for children born to HCV-positive mothers.3,4
Results From The Qualitative Test
Doctors use the qualitative HCV RNA PCR test to determine whether or not the hepatitis C virus is present in the blood.
If the virus is present, the test will be positive. If the test does not detect the virus, the result will be negative.
If the result is positive, a person will then need a quantitative HCV RNA PCR test. For this reason, many doctors now prefer to skip the first test and use the quantitative test straight away.
The quantitative test results show how much HCV is in the body. However, whether low or high, the viral load does not reflect levels of damage to the liver.
Other blood tests, ultrasounds, and, rarely, a liver biopsy will help a doctor determine overall liver health.
After using an HCV RNA PCR test to confirm the presence of HCV, doctors will work out which strain of the virus is active in the body. This helps a doctor plan the course of treatment.
The primary goal of treatment is to bring down the viral load in the body until it is entirely free of the virus. Doctors know this as a sustained virologic response .
SVR occurs when the virus is undetectable for 12 weeks or longer after treatment.
Achieving SVR is the best outcome of treatment, as it often means the person is free from hepatitis C, or that treatment has cured hepatitis C.
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What To Know About Hepatitis C Testing
The HCV RNA PCR test is a blood test that helps a doctor diagnose hepatitis C. The test measures the level of the hepatitis C virus in the bloodstream.
Hepatitis C is an infection that causes scarring in the liver and reduces function in this vital organ. Severe HCV can lead to liver failure. However, early diagnosis can reduce the risk of severe infection.
In this article, we look at how the test works and what the results mean.
The HCV RNA PCR test is a blood test. A lab technician looks for the genetic material of the HCV virus, or its ribonucleic acid . They use a process called a polymerase chain reaction .
The results of the HCV RNA PCR test help a doctor recommend different ways of reducing the viral load. The viral load indicates how many HCV viral particles are in the blood.
If a doctor suspects that a person has HCV, they will recommend this test early on in the diagnostic process, even if it is not the first test they carry out.
The test can detect the presence of the virus itself, rather than the antibodies that the body creates in response to the virus.
This means that a person does not have to wait until symptoms of the infection develop for a diagnosis.
It can take an average of 68 weeks for antibodies to become detectable after an HCV infection begins. However, a doctor can identify the virus itself after about 1-2 weeks by using PCR or another means of direct virus detection.
Doctors use the HCV RNA PCR in one of two ways:
When Should I Get Hepatitis C Testing
When used for early detection in patients without symptoms of hepatitis C, screening is recommended at least once for all adults aged 18 years or older, except in locations with very low prevalence of HCV. Screening is also recommended during pregnancy and for patients of any age with risk factors for HCV infection. In patients with risk factors, periodic screening is recommended for as long as risk factors persist.
Risk factors for HCV include:
- Current or past injectable drug use
- Having a blood transfusion or organ transplant before July 1992
- Receiving kidney dialysis
- Pain in the abdomen or joints
- Nausea, vomiting, or loss of appetite
- Jaundice or yellowish skin and eyes
Hepatitis C testing may also be performed when liver tests are abnormal or when diagnosing the cause of existing liver damage.
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Questions For Your Doctor About Test Results
Patients receiving hepatitis C testing may find it helpful to ask questions about their test results. Questions to consider include:
- What type of hepatitis C test did I receive?
- What was my test result?
- How do you interpret the results of the hepatitis C tests that I had?
- Do I need any follow-up tests based on my test result?
Nat: Detection Of Hcv Rna
Molecular virological techniques play a key role in diagnosis and monitoring of treatment for HCV. Because it is difficult to cultivate the virus in cell culture, molecular techniques were instrumental in first identifying HCV, making it one of the first pathogens to be identified by purely molecular methods. NAT is considered the gold standard for detecting active HCV replication. HCV NAT is extremely useful in establishing the diagnosis of acute HCV infection, since RNA is detectable as early as 1 week after exposure via needle-stick or blood transfusion, and at least 4-6 weeks prior to seroconversion as demonstrated in a number of transmission settings. The diagnosis of HCV infection is established with antibody screening followed by NAT for HCV RNA for confirmation as well as for follow-up of patients on treatment. Viral load assessment at baseline is also critical for determining response kinetics during therapy. enumerates the role of NAT in HCV diagnosis.
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Hcv Core Antigen Detection
During the past decade, several assays for the detection of the core antigen of HCV by ELISA or CLIA have been developed. These assays were envisioned as alternatives to NAT to be used in resource-limited settings, where molecular laboratory services are either not available or not widely utilized owing to cost issues. Since these assays are either ELISA or CLIA based, they are user friendly, require less technical expertise and are less expensive compared to molecular techniques. Evaluations in transfusion settings have shown that the HCVcore Ag assay detects HCV infection as effective as NAT, about 40-50 days earlier than the current third generation anti-HCV screening assays. HCV core antigen levels closely follow HCV RNA dynamics, and allow clinical monitoring of a patient’s therapy, independently of HCV genotype. The major limitation of the HCV core Ag assay is its lower sensitivity limiting its utility. A new generation CLIA based quantitative test with sensitivity comparable to that of end point PCR but less than that of real time RT-PCR has been reported.
Understanding Of Lab Tests Results
Please visit the site associated with The American Association for Clinical Chemistry for better understanding of tests. There you will find the most detailed and full information regarding lab tests. In “common questions” tab you will find answers on the most common questions.
In addition, you can use a special form to ask the question. It is useful, if there is no answer on your question on the web site. A laboratory scientist will answer your question. It is a part of voluntary service provided by the American Society for Clinical Laboratory Science.
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Natural History Following Infection With Hcv
Hepatitis C can present as acute or chronic hepatitis. Most of the cases of acute hepatitis C are asymptomatic. Symptomatic acute hepatitis with jaundice is seen in 10-15% of patients only and can be severe, but fulminant liver failure is rare. Spontaneous clearance is observed in 25-50% of those with symptomatic infection and in 10-15% of those with asymptomatic infection. The natural history following exposure to HCV is summarized in .
Natural history following infection with hepatitis C virus
Chronic hepatitis C is marked by the persistence of HCV RNA in the blood for at least 6 months after the onset of acute infection. The risk of progression to chronic infection by HCV is influenced by various factors including:
Age at the time of infection
Coinfection with human immunodeficiency virus , HBV
Concomitant alcohol consumption
Comorbid conditions like cancer, immunosuppression, insulin resistance, nonalcoholic steatohepatitis, obesity, etc.
Hepatitis C Virus Antibody With Reflex To Hcv Rna Pcr Symptomatic Serum
Diagnosis of recent or chronic hepatitis C virus infection in symptomatic patients
This test is not offered as a screening or confirmatory test for hepatitis C virus for blood, human cells, or tissue donors.
This test profile is not useful for detection or diagnosis of acute HCV, since HCV antibodies may not be detectable until after 2 months following exposure and HCV RNA testing is not performed on specimens with negative anti-HCV screening test results.
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Question 7 What Proportion Of Hcv Antibody
Among specimens with reactive HCV antibody results, approximately 52% have detectable HCV RNA at a level of > 15 IU/mL on reflex testing. However, the frequency varies markedly based on the strength of the signal of the antibody test, or signal-to-cutoff ratio. Specimens with an S/C ratio of at least 1.0 are considered reactive for HCV antibody7 and thus undergo reflex testing for HCV RNA. Analysis of approximately 200,000 specimens submitted to Quest Diagnostics for HCV antibody testing with reflex to HCV RNA testing demonstrate that the frequency of positive reflex results increases with increasing S/C ratio:
Question 10 I Am Treating My Hcv
If HCV RNA is detectable at week 4 of treatment, per AASLD guidelines, it is suggested to repeat quantitative HCV RNA viral load testing after 2 additional weeks of treatment. If quantitative HCV RNA testing at week 6 of treatment shows an increase of greater than 10-fold , discontinuation of HCV treatment is recommended. The cause of a positive HCV RNA test result at week 4, with decreasing levels at week 6 or week 8, is unknown. There is no recommendation to stop therapy or extend therapy for these patients.9
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