Why Are There Often Blood Shortages
Most blood centers strive to maintain an optimum inventory level of a three-day supply. Due to unpredictable demands, the inventory often fluctuates hourly. When the blood supply drops below a three-day level, blood centers begin alerting local donors to increase the inventory to a safe operating level.
How Do Doctors Diagnose Hepatitis A
Doctors diagnose hepatitis A based on symptoms and a blood test. A health care professional will take a blood sample from you and send the sample to a lab. A blood test will detect antibodies to the hepatitis A virus called immunoglobulin M antibodies and show whether you have acute hepatitis A. If the blood test finds antibodies to the hepatitis A virus that are not IgM antibodies, then you are immune to hepatitis A, due to either past hepatitis A infection or hepatitis A vaccination.
Tests We Carry Out On Your Blood
You may have noticed that each time you give a blood donation we also take blood samples.
These samples are used to perform a range of screening tests in our laboratories.
Most of these tests are mandatory, in other words we must carry them out on every single blood donation, whether this is your first donation or just one of the many you have given over the years.
However, there are some additional tests that may need to be done on some donations as necessary.
Sometimes the tests cannot be done, for example – if you give an incomplete blood donation or no blood samples are obtained, or if we cannot take a donation because of poor veins or you have low haemoglobin level for blood donation.
The tests play a very important role in ensuring that we provide a safe blood supply to patients. We test for your blood group, so that we can select the correct group for the patient.
We also test for infections that can be passed from donor to patient via a blood transfusion.
The tests are carried out by computer-controlled automated machines which can test many samples both quickly and easily, so helping us to get blood to the hospitals as fast as we can.
Any donation that is reactive on any one of the screening tests cannot be used. If your blood is reactive on any one of the screening tests, further tests are carried out to confirm whether the result indicates a true infection.
If the test results show that you can no longer give blood, then you will be given specific advice.
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Role Of Hbv Vaccination
Locarnini and Raimondo express in their commentary the expectation that universal hepatitis B immunization will more often protect recipients against HBV in blood donations. Even passively administered anti-HBs by concomitant donations from immunized donors protects against donations from OBI donors . The downside of vaccination is that it does not completely protect and that vaccinated donors with low or absent anti-HBs may develop after exposure an acute quasi-occult HBV infection which can only be detected by NAT. This incomplete protection occurs rarely but in increased frequency when the infecting HBV strain has a genotype different from the vaccine strain . This side effect should definitely not deter blood donation services to accept vaccinated donors with low anti-HBs. A better consequence would be that responsible institutions like pharmaceutical industry and WHO would consider the possible improvements of current HBV vaccines like use of the regional predominating HBV genotypes or preS1 containing vaccines . Unnoticed OBI of vaccinated individuals detectable by anti-HBc occurs very often in highly endemic countries. In the worst case only highly sensitive NAT can detect a recent occult HBV infection in anti-HBs positive vaccinated individuals .
Blood Donation And Mad Cow Disease
People who spent 6 months or more in the UK between 1980 and 1996 are currently unable to donate. This is due to the possibility that they may have vCJD , a human form of BSE or mad cow disease.
This condition cannot yet be tested for and may remain dormant for a very long time. Similar precautionary measures apply to donors in New Zealand, Canada and the USA.
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Does Donated Blood Stay On The Shelf Indefinitely Until It Is Used
No. Each unit of whole blood is separated into several components. Red blood cells may be stored under refrigeration for a maximum of 42 days, or frozen for up to 10 years. Platelets are stored at room temperature and may be kept for a maximum of five to seven days. Fresh frozen plasma is kept in a stored frozen state for up to one year. Cryoprecipitated AHF is stored frozen for up to one year. Granulocytes must be transfused within 24 hours of donation.
Other products manufactured from blood include albumin, immune globulin, specific immune globulins, and clotting factor concentrates. Commercial manufacturers commonly produce these blood products.
Why A False Positive Happens
A doctor will consider two factors when reviewing the accuracy of a test result. These two factors are the tests specificity and sensitivity.
Specificity refers to the ability of a test to correctly identify those who do not have a disease. This is called the true negative rate.
Sensitivity reflects the ability of a test to correctly identify those who do have a disease. This is called the true positive rate.
According to a , third-generation anti-HCV tests have an average specificity of 97.5% to 99.7%. The sensitivity of these tests varies from 61.0% to 81.8%.
These findings indicate that anti-HCV tests detect true negatives more accurately than true positives .
A person may receive a false-positive test result if they have HCV antibodies from a previous active infection. They may have received successful treatment for this infection, or their body may have cleared it without treatment.
In either case, the antibodies from the previous infection can remain in the body and lead to positive results on anti-HCV tests.
False-positive results can also occur in children who had HCV transmitted to them during birth from a mother with hepatitis C virus infection.
Ultimately, a person who receives a positive result from an anti-HCV test may not have an active hepatitis C infection. This is why a doctor then typically performs another test the HCV RNA RT-PCR test before making a definitive diagnosis.
People who do not have hepatitis C can often prevent exposure to it by:
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Whats The Hepatitis B Titer Test Used For
A hepatitis B titer test measures antibodies in your blood to see if youre immune either due to vaccination or previous infection.
Hepatitis B is a viral infection that targets your liver. It can be transmitted by coming into contact with the bodily fluids of an infected person. A person with the virus can also infect their child during birth.
Hepatitis B can develop into a chronic infection. Chronic infection occurs when your body cant fight off the virus within six months. Chronic hepatitis B infections most commonly develop less than six years old, especially in infants.
Hepatitis B titer tests can be used to evaluate:
- whether a high-risk person is immune to hepatitis B
- whether hepatitis B immunoglobulin is needed after a needle prick
- men who have sex with men
- people born in countries with a hepatitis B prevalence greater than 2 percent
- people born in the United States not vaccinated as children and with parents born in regions with more than 8 percent hepatitis B prevalence
You may need your titer test results as proof of hepatitis B immunity in order to get into healthcare programs at many schools for example, the nursing program at Lone Star College. In the United States, employers are not allowed to withdraw a job offer if they learn you have hepatitis B.
How Common Is Hepatitis A
In the United States, hepatitis A has become relatively uncommon. After the hepatitis A vaccine became available in 1995, the rate of hepatitis A infections declined by 95 percent in the United States. The number of reported cases of hepatitis A fell to 1,239 in 2014, the lowest yearly number of cases reported since the disease could be tracked.1 However, the number of reported cases increased to 3,366 in 2017, almost 3 times higher, mostly due to outbreaks among people who use drugs and people experiencing homelessness.1 Early reports suggest that the numbers of cases and outbreaks of hepatitis A increased further during 2018 and continue at these higher rates in 2019.2
Hepatitis A is more common in developing countries where sanitation is poor and access to clean water is limited. Hepatitis A is more common in parts of Africa, Asia, Central and South America, and Eastern Europe than it is in the United States.
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Other Things To Know:
- After a successful course of treatment for hepatitis C, the hepatitis C antibody remains detectable, but the hepatitis C RNA will be undetectable.
- If you plan to donate blood, you will be tested for the hepatitis C antibody and will be turned away even if you do not have an active infection.
- Any patient with a positive test result for the hepatitis C antibody should have additional tests to determine whether or not the virus is still active.
Explanation Of Test Results:
If this test result is positive, it means your body was exposed to the hepatitis C virus and made antibodies . However, it does not tell you whether you are still infected with hepatitis C. If the antibody test result is positive, you should be tested for hepatitis C RNA , which determines whether you are chronically infected. The lab will perform this RNA test automatically if your hepatitis C antibody test is positive.
If the antibody test result is negative, it means you have not been infected with the hepatitis C virus, and further testing for hepatitis C usually is not needed.
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Gaps Left By Current Nat Testing
Transmission of HBV by NAT negative donations was repeatedly reported as summarized by Candotti and Laperche . Infection experiments with chimpanzees or humanized mice suggest that one single HBV particle from early phase sera may induce a full HBV infection whereas particles from later still HBsAg positive phases are usually less infectious . The recent paper from Candotti et al. provides deeper insight because it shows that in certain OBI cases HBV particles may be as infectious as particles from the early phase. Furthermore, the study illuminates the difficulties to follow-up and identify infected recipients unless the follow-up of recipients and look-back of donors with suspected donors is consequently pursued . This observation takes the minimum requirements for HBV screening procedures to a new dimension if optimum safety at all economic cost is pursued: NAT screening should be applied to all donations at a limit of 95% detection of 0.8 ge/mL which would require testing of several mL of single donations and virtually exclude minipool testing.
Who Can Donate Blood
Healthy adults who meet donation eligibility criteria can donate blood. The procedure is safe and relatively painless.
During a regular donation, you will give around 470ml of whole blood. This is about 8% of the average adults blood volume.
The body replaces this volume within 24 to 48 hours, and replenishes red blood cells in 10 to 12 weeks.
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What Is A Hepatitis B Surface Antibody Test
Hepatitis B surface antibody test is part of a panel of blood tests to diagnose HBV infection. Hepatitis B surface antibody test determines the presence and quantity of anti-HBs in the blood serum, which can indicate protection from HBV infection.
Hepatitis B disease affects the liver and commonly spreads through body fluids such as blood, semen, and vaginal secretions.
Hepatitis B Core Antibody Positive Donors
UC Davis has also maximized organ placement through the use of organs from hepatitis B core antibody positive donors. These donors have been exposed to hepatitis B in the past but test negative for the more serious hepatitis B surface antigen. These organs are used only in recipients who have antibody against hepatitis B. Further testing is done to check the donor for actual hepatitis virus in the blood, which is very rare. This test takes several days and the results will not be available before the transplant. The recipient is treated with anti-viral medications until the results come back and if they are positive, the anti-viral treatment would continue for a longer period of time. Anti-viral treatments for hepatitis B are very effective and well tolerated. We have safely transplanted many patients using hepatitis B core antibody positive donor organs.
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What Causes Hepatitis A
The hepatitis A virus causes this type of hepatitis and spreads through contact with an infected persons stool. Contact can occur by
- eating food made by an infected person who did not wash his or her hands after using the bathroom
- drinking untreated water or eating food washed in untreated water
- placing a finger or an object in your mouth that came into contact with an infected persons stool
- having close personal contact with an infected person, such as through sex or caring for someone who is ill
You cannot get hepatitis A from
- being coughed on or sneezed on by an infected person
- sitting next to an infected person
- hugging an infected person
A baby cannot get hepatitis A from breast milk.4
Identifying Patterns Of Risky Behavior
Screening is an opportunity to draw attention to the clients behaviors that put him or her at risk for contracting :
- Ask for the clients perception of his or her risk for having contracted : How likely do you think it is that the test will be positive?
- Listen for and identify behaviors that put the client at risk for contracting , B, and C and HIV, especially unprotected sex and sharing injection drug paraphernalia.
- Assess the clients alcohol consumption.
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Detection Of Serologic Markers
Qualitative assays for HBV serology and quantitative assay for anti-HBs, were performed using commercial kits on the automated ARCHITECT i6000 analyzer according to manufacturer’s instructions on all study samples. Both anti-HBc Total and anti-HBc IgM S/CO 1 results were considered reactive. Anti-HBs levels were expressed in International Units per liter .The assay is linear from 2 to 1,000 IU/L. Serum anti-HBs titers 10 IU/L was considered positive following WHO recommendations.
What Does The Term Donor Deferral Mean
Donor deferral means that an individual is not eligible to donate based on the criteria used to protect the health and safety of both the donors and transfusion recipient. A prospective donor may be deferred at any point during the collection and testing process. The period of time you will not be eligible to donate depends on the specific reason for deferral. After the deferral period ends, a donor can return to the blood donor center to be reevaluated and resume donation if all donor eligibility criteria are met.
Blood donor centers follow donor eligibility criteria based on requirements of the FDA, AABB Standards, and their own local policies. The blood centers medical director has ultimate authority and can establish a more stringent deferral policy based on clinical judgement as a physician. Refer to the AABB Blood Donor History Questionnaire for examples of the questions asked during the donor screening process. Your blood donor center can best answer your questions about donor deferral. Some of the reasons for deferral are listed here:
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Early Phase Hbv Infections
However, not all HBV-infected individuals have very high concentrations of HBsAg. Donors in the early phase of the infection have still low viremia and a not-yet activated immune response to HBV. It is obvious that in this phase the most sensitive assays for HBsAg are required, and nevertheless a recently infected donor may be missed. Here, we will briefly discuss the strengths and weaknesses of current HBsAg tests and the efforts to standardize HBsAg assays for objective external quality control.
Negative But Other Hepatitis Tests Are Positive
Your HBsAb test may be negative even when other hepatitis B tests are positive, showing active or chronic infection. Further testing is necessary, especially for the hepatitis B surface antigen , which shows that the virus itself is circulating in your bloodstream and that you have an active or chronic infection.
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What Happens At My First Medical Research Appointment
At your first appointment you will receive an information form that outlines the purpose of the research, and a consent form to sign.
The blood collection procedure takes about 15 minutes, is safe, and is performed by a fully trained scientist, nurse or doctor. The amount of blood taken depends on the needs of the research project, but will range from 40 to 400ml. Your body will need only a couple of days to replace 400ml of blood.
You will be paid a small amount at each visit to help cover transportation or other costs.
Most people can donate regularly. If you indicate that you would be willing to give future blood donations, your name and contact details will be kept on a database for blood donation requests once every 3 months .
If you wish, you can receive information on the results of the research project.
If you have a complaint about any aspect of the research, contact the Standing Committee on Ethics in Research on Humans via the Ethics and Compliance Team.
Does Hepatitis B Show Up In Routine Blood Tests
Routine blood tests do not detect hepatitis B virus infection. Hepatitis B tests are specifically done if blood tests show abnormal liver function results, or if a person experiences symptoms or falls into the high-risk category for HBV infection.
A panel of HBV-specific blood tests are required to detect HBV infection.
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