Friday, November 25, 2022

Hepatitis C Virus Antibody With Reflex To Pcr

Meaning Of Hcv Viral Load

Viral Hepatitis C

The number of HCV RNA international units per milliliter of blood must be measured before treatment and during the course of treatment, to assess response. Before treatment, however, the HCV viral load is not related to the patient’s liver disease severity or HCV prognosis. This is important for patients and providers to understand.

Note: In hepatitis B, unlike hepatitis C, a higher HBV DNA viral load does correlate with increased disease severity and increased likelihood of outcomes such as hepatocellular carcinoma.

Are Test Results Accurate

Although no test is perfect, hepatitis C testing is an important and accepted method of testing for HCV. In order to reduce the risk of inaccurate results, doctors take steps to verify a patients diagnosis. For example, a positive test result for hepatitis C antibody requires confirmation with HCV RNA testing.

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A single negative hepatitis C virus RNA test result together with a reactive HCV antibody screen result with a signal-to-cutoff ratio of 8.0 or greater does not rule out the possibility of chronic HCV infection. Repeat testing for HCV RNA in 1 to 2 months is recommended in patient at risk for chronic hepatitis C.

Infants born to HCV-infected mothers may have false-reactive HCV antibody test results due to transplacental passage of maternal HCV IgG antibodies. HCV antibody testing is not recommended until at least 18 months of age in these infants.

Performance characteristics have not been established for the following types of serum specimen:

-Individuals under 10 years of age

-Grossly icteric

-Grossly lipemic

-Grossly hemolyzed

-Presence of particulate matter

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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.

Discusses Physiology Pathophysiology And General Clinical Aspects As They Relate To A Laboratory Test

HCV &  other Hepatitis Viral Infection

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

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The Quantitative Hcv Rna Test Is Checked Before A Patient Starts Treatment

For each patient, the result can be described as either a “high” viral load, which is usually > 800,000 IU/L, or a “low” viral load, which is usually < 800,000 IU/L. It’s not uncommon to have a viral load in the millions. Today’s hepatitis C treatments are very effective with both high and low viral loads. An undetectable HCV viral load 10-12 weeks after hepatitis C is completed is associated with a cure.

What Does The Test Measure

Hepatitis C testing identifies antibodies to the hepatitis C virus, detects viral RNA, and/or determines the strain of hepatitis C. Hepatitis C testing may involve several different tests:

  • Hepatitis C antibody test: Antibodies are a part of the bodys response to an infection. Testing for hepatitis C antibodies determines whether or not a patient has been exposed to the hepatitis C virus at some point in their life. If this test is positive, the next step is to test for hepatitis C RNA which can tell you if you have a current infection.
  • Hepatitis C RNA test: RNA is a type of genetic material from the hepatitis C virus that can be detected in the blood. If test results are positive after a hepatitis C antibody test, doctors use a hepatitis C RNA test to look for and/or measure the amount of the virus in the blood. Qualitative HCV RNA tests can detect the presence of HCV RNA, while quantitative HCV RNA tests measure the amount of HCV RNA. Understanding the amount of HCV in the blood helps to monitor response to treatment.
  • Genotype test: There are at least six types of hepatitis C, which are also called strains or genotypes. Treatment for hepatitis C depends on the strain, so genotype testing to guide treatment is performed in patients who are diagnosed with an HCV infection.

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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.

Methodology: Immunoassay

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.

Taking A Hepatitis C Test

Hepatitis C Infection with Case â Disorders of the Hepatobiliary Tract | Lecturio

Hepatitis C testing is conducted on a sample of blood. Blood samples can be collected by a doctor, nurse, technician, or other health care provider from an adult patients vein using a small needle or a skin prick on a childs heel.

For an at-home hepatitis C test, patients collect a blood sample according to the manufacturers directions. Instructions provided in the test kit detail the steps to obtain a small sample of blood and mail it for testing.

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Role Of Hcv Core Antigen In Monitoring During And After Therapy

Monitoring HCV viral load with HCV core antigen during antiviral treatment might be an attractive tool for the future. Unfortunately data are too limited for strong recommendations thereof .1). Especially, there are no data with the newer antivirals available at present. For Pegylated Interferon plus Ribavirin regimens, there have been some studies suggesting that one can predict response as early as day 3, week 1 or week 2.

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.

Doctors will also combine treatments with other tests that monitor for complications of HCV, including cirrhosis and liver cancer.

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Other Things To Know:

  • The viral load measurement does not tell us anything about the severity of a patient’s liver disease or the degree of fibrosis . For that information, the patient would need additional testing.
  • It is not necessary to check the viral load repeatedly during treatment.
  • If a quantitative HCV RNA result is reported as “< 15 IU/L,” this means that the quantitative test cannot measure the hepatitis C virus. It may mean that there is no detectable HCV RNA at all, but it may mean that the level of virus is just too low for the test to pick it up.

How To Get Tested

G. Diagnosis

Hepatitis C testing is performed by a doctor. Testing requires a blood sample, which can be collected in a hospital, lab, or other medical setting. Blood is often drawn from a vein in the arm or, in children, taken by pricking the skin. After blood is collected, the sample is sent to a laboratory for analysis.

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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.

Enzyme Immunoassays For Detection Of Hepatitis C Antibody

The HCV Ab test is used for initial screening for hepatitis C. The test is performed by enzyme immunoassays , which detect the presence of hepatitis C antibodies in serum. The result of the test is reported as positive or negative. Third-generation EIAs have a sensitivity/specificity of approximately 99%. However, the presence of HCV Ab does not indicate whether the infection is acute, chronic, or resolved. A positive antibody test result should be followed up with an HCV RNA test to confirm that viremia is present.

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How Much Does The Test Cost

The cost of hepatitis C testing depends on the tests that are performed, where the test is conducted, and a patients health insurance coverage. When testing is ordered by a doctor, patients with health insurance may find it helpful to discuss the cost of hepatitis C testing with their insurance company. In addition to the cost of testing, there may be other out-of-pocket costs such as copays and deductibles.

For patients without health insurance, or for whom insurance doesnt cover the cost of testing, it may be helpful to discuss the cost of hepatitis C testing with a doctor or hospital administrator.

At-home hepatitis C testing starts around $49. Some at-home kits test for multiple types of viral hepatitis at once, with the cost of these panels starting around $80.

Role Of Hcv Core Antigen In A Blood Bank/organ Donor Setting

RT-PCR vs Rapid Antigen Test

As outlined above, the sensitivity of HCV core antigen is inferior to HCV RNA, but superior to no testing. Thus, in a resource limited setting, where HCV RNA testing might be impossible due to cost restrains at present, HCV core antigen testing would allow for a compromise.

Given the cost of organ transplantation, HCV RNA testing cost is unlikely to be a rate limiting step, and therefore not likely to be relevant to organ donation. Still if currently no HCV RNA testing is performed, HCV core antigen might be better than no testing for infectivity.

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New Testing Options For Hepatitis C Virus

2017, Volume 27, Number 2

Danny L. Wiedbrauk, Ph.D., Scientific Director, Virology and Molecular Biology

Warde Medical Laboratory has a new testing option for diagnosing Hepatitis C Virus infections. The test, Hepatitis C Virus Antibody with Reflex to PCR includes HCV antibody testing with automatic referral to PCR for antibody-Reactive specimens. A final interpretation, based upon CDC guidelines, is provided for all specimens.

This testing protocol requires submission of two separate sample tubesone serum, the other plasma. The serum tube is tested for HCV antibody and if Reactive, the plasma tube is tested for HCV RNA by a quantitative PCR protocol.

Testing For Hepatitis C

Two tests need to be done to discover if you have hepatitis C:

  • Antibody test: Which establishes whether you have ever been exposed to the hepatitis C virus.
  • PCR test: Which establishes whether the virus is still active and needs treating.

The two tests can often be done from one sample of blood which means you may only need to provide the sample once. Both tests can then be done on your sample at the laboratory. However, some services will perform one test and then call you back for a further blood sample to perform the second test.

Antibody test

A hepatitis C antibody test is the first test undertaken. This is to determine whether you have ever been exposed to the hepatitis C virus. It works by testing for the presence of antibodies to the virus generated by your immune system. If you receive a negative hepatitis C antibody test but have been experiencing symptoms or have been recently exposed to hepatitis C, then you are likely to be advised to have a second test.

It is important to remember that there is a ‘window period’. This is the short period of time when your immune system may not have had time to produce antibodies. It usually takes between six and twelve weeks for these antibodies to develop. However, in a few people it can take up to six months. So if you have the test within this window period and the result is negative, it does not necessarily mean that you don’t have the virus.

PCR test

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Interpreting Hcv Rna Test Results

It is essential that the provider understands how to interpret HCV RNA test results, especially during the course of HCV treatment.

Result of HCV RNA Test Interpretation
A quantified viral load — any exact number Ongoing HCV infection
“Detected” The HCV RNA is detectable but the number of international units is so low that it cannot be quantified accurately. This indicates extremely low level of virus is present.
“< 12 IU/mL” or “< 15 IU/mL” or “< 25 IU/mL” All of these are “less than the LLOQ” HCV RNA is undetectable. No virus is detected at all in the patient’s serum specimen.

Time For Processing Hcv Ab Test Results

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The turnaround time for 3rd-generation EIAs is at least 1 day. Many labs do not perform the tests on site and must send specimens to another lab for processing, which may further increase the turnaround time.

A point-of-care test is also available. The OraQuick® HCV Rapid Antibody Test is an FDA-approved test that can be performed with a fingerstick . It is also a CLIA-waived test and therefore can be used in clinic offices and outreach facilities. Results are reported as reactive or nonreactive within 20 minutes. Just as for the standard HCV Ab test done in the lab, a positive OraQuick® test must be confirmed by an HCV RNA test. The sensitivity and specificity of the test is similar to that of the laboratory-based assays.

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Hepatitis C Antibody With Reflex To Pcr

Hepatitis C Ab w/RFLX PCR
Lab Code
Hepatitis C Antibody w/Reflex PCR
Description

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 .

Synonyms

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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