PREFERRED: Serum is the preferred specimen. Collect blood in a 4 ml Gold Serum Separator Tube-Clot Activator & Gel.
REMARK: Plasma is an acceptable alternative specimen. Blood can be collected in plastic tubes containing dipotassium EDTA with or without gel separator, lithium heparin with gel separator, and sodium heparin.
4 ml of blood
2 ml of blood
A total of 2-4 ml of blood (for every 2-3 Hepatitis and HIV tests ordered) should be collected.
For the CHOP enterprise, submit blood specimens as soon as possible at room temperature to Central Laboratory Services.
For outside clients, it is recommended that serum or plasma specimens be removed from the clot, red blood cells, or separator gel as soon as possible after collection and before shipping specimens. When shipping serum or plasma specimens, package and label specimens in compliance with applicable state, federal, and international regulations covering the transport of clinical specimens and infectious substances. Specimens may be shipped at 2-8C (wet ice) or frozen (dry ice). Do not exceed the storage time limitations listed under the heading of Stability.
Serum or plasma specimens should be stored for no longer than 3 days at room temperature or 7 days at 2-8C following specimen collection and separation from clot, red blood cells, or separator gel. If a storage period greater than 7 days is anticipated, serum or plasma should be stored frozen at -20C or colder. No more than 3 freeze-thaw cycles should be performed on any sample prior to testing, and specimens should not be stored in frost-free freezers.
Do not use serum or plasma specimens that are heat-inactivated, pooled, grossly hemolyzed, or contain obvious microbial contamination. Performance has not been established for the use of cadeveric specimens or the use of boody fluids other than human serum or plasma.
Unprocessed blood specimens should routinely be refrigerated at 4C upon arrival in the laboratory. One should remove the serum or plasma from clotted blood, red blood cells, or separator gel as soon as possible to avoid hemolysis. The best results are generally observed for serum or plasma specimens that are clear and nonhemolyzed. Lipemic, icteric, or hemolyzed specimens should be avoided when possible, and specimens with obvious microbial contamination should not be used. Specimens containing unremoved clots, red blood cells, or particulate matter may give inconsistent results and should be clarified by centrifugation before testing.
Monday thru Friday
Chemiluminescent microparticle immunoassay
Detecting HCV-specific IgG antibody by enzyme immunoassay remains the first choice for diagnosis of HCV infection. Antibodies to HCV become detectable during the course of illness, with 50-70% of patients having anti-HCV antibodies at the onset of symptoms and approximately 90% of patients having an HCV-specific antibody response within 3 months after onset of infection. Anti-HCV antibodies persist in the serum of most patients that have been infected, but loss of antibody may occur in individuals with resolved acute infection, immunosuppressed organ transplant recipients and those with HIV, and following interferon therapy. Antibodies to HCV can be demonstrated in virtually all patients with chronic HCV hepatitis. The presence of anti-HCV IgG indicates that an individual may have been infected with HCV in the past or may have an ongoing HCV infection. Supplemental PCR testing for the molecular amplification of HCV RNA is used to discriminate chronic HCV infections from resolved acute infections in patients who are positive for HCV antibody. The “window period” from infection to seroconversion can be quite long for HCV, as antibody responses may not be detectable until 10 weeks after the onset of hepatitis. Therefore, sensitive molecular-based assays for the detection of HCV RNA can be used to detect HCV within 2-3 weeks following exposure to the virus to detect HCV-infected individuals prior to specific antibody production.
The presence of HCV antibody is indicative of either a past or present infection with hepatitis C virus. Virtually all patients with chronic HCV infection will be positive for HCV antibody. A positive screening serological test for HCV antibody should be followed by a PCR test to confirm the presence or absence of HCV RNA in the individual’s blood. A negative result is indicative of no evidence of a recent, past or chronic infection with HCV. It does not exclude the possibility of exposure to or early acute infection with HCV. Individuals with recent HCV infections (<3 months from time of exposure) may have false-negative HCV antibody results due to the length of time it takes to seroconvert following initial infection. If you suspect an acute HCV infection, please also order an HCV RNA PCR. HCV RNA can be detected in blood within 1-3 weeks of exposure.
Negative or nonreactive for hepatitis C virus (HCV) antibody
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