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HelpTest Code HEVML Hepatitis E Virus IgM Antibody Confirmation, Serum
Reporting Name
HEV IgM Ab Confirmation, SUseful For
Confirmation of reactive hepatitis E virus IgM antibody screening test results for the diagnosis of acute or recent (<6 months) hepatitis E infection
Testing Algorithm
For information see Hepatitis E: Testing Algorithm for Diagnosis and Management.
Method Name
Line Immunoassay (LIA)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum SSTNecessary Information
Date of collection is required.
Specimen Required
Collection Container/Tube: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Centrifuge blood collection tube per collection tube manufacturer's instructions (eg, centrifuge and aliquot within 2 hours of collection for BD Vacutainer tubes).
2. Aliquot serum into plastic vial.
Specimen Minimum Volume
0.2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum SST | Frozen (preferred) | ||
| Refrigerated | 7 days | ||
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Special Instructions
Reference Values
Negative
Day(s) Performed
Every other Friday
CPT Code Information
86790
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HEVML | HEV IgM Ab Confirmation, S | 14212-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 61903 | HEV IgM Ab Confirmation, S | 14212-5 |
Clinical Information
Hepatitis E virus (HEV) causes an acute, usually self-limited, infection. This small, non-enveloped RNA virus is from animal reservoirs (eg, hogs) and is transmitted to humans via the fecal-oral route. HEV is endemic in Southeast and Central Asia, with several outbreaks observed in the Middle East, northern and western parts of Africa, and Mexico. In developed countries, HEV infection occurs mainly in individuals who have traveled to disease-endemic areas. Transmission of HEV may also occur rarely from direct person-to-person contact or transfusion of blood or blood products. Clinically severe cases occur in young to middle-aged adults. Unusually high mortality (approximately 20%) occurs in women infected during the third trimester of pregnancy. Although there is no carrier state associated with HEV, patients who are immunocompromised may have prolonged periods (eg, months) of viremia and virus shedding in the stool.
In immunocompetent individuals, viremia and virus shedding in the stool occur in the pre-icteric phase, lasting up to 10 days into the clinical phase. After an incubation period ranging from 15 to 60 days, patients infected withHEV develop symptoms of hepatitis with appearance of anti-HEV IgM antibody in serum, followed by detectable anti-HEV IgG within a few days. Anti-HEV IgM may remain detectable up to 6 months after onset of symptoms, while anti-HEV IgG usually persists for many years after infection. Anti-HEV IgM is the serologic marker of choice for diagnosis of acute HEV infection.
The positive predictive value of a given diagnostic laboratory test is dependent on the prevalence rate of the disease for which the test is being used. Screening tests for detection of diseases with low prevalence rates, such as acute hepatitis E, will have low positive predictive values (ie, relatively high rates of false-positive test results), despite having high specificity rates for such tests. Therefore, an HEV IgM antibody confirmatory test is helpful and necessary to determine the true infection status of patients with reactive HEV IgM antibody screening test results.
Interpretation
Positive results confirm the presence of acute or recent (in the preceding 6 months) hepatitis E infection.
Negative results indicate absence of acute or recent hepatitis E infection.
Indeterminate results may be seen in:
1. Acute hepatitis E infection with rising level of anti-hepatitis E virus (HEV) IgM
2. Recent hepatitis E infection with declining level of anti-HEV IgM
3. Acute hepatitis E infection due to HEV genotype 2 strains
4. Cross-reactivity with nonspecific antibodies (ie, false-positive results).
Repeat testing of serum for anti-HEV IgM and anti-HEV IgG in 4 to 6 weeks is recommended to determine the definitive HEV infection status.
Unreadable results indicate the presence of unusually strong, nonspecific reactivity of the assay strip background that obscures proper reading of the bands. Such findings are usually due to nonspecific binding of non-hepatitis E IgM antibodies in patient's serum to the HEVM antigens present on the assay strip. Repeat testing with anti-HEV IgM screen and anti-HEV IgG in 4 to 6 weeks is recommended.
Cautions
A negative test result does not exclude the presence of recent hepatitis E infection, especially in patients who are immunocompromised. Repeat testing of serum for anti-hepatitis E virus (HEV) IgM in 2 weeks may be necessary for diagnosis of acute or recent hepatitis E infection.
A positive result does not always indicate the presence of active disease.
Performance characteristics of this assay have not been established for serum specimens that are icteric, lipemic, hemolyzed, or contain particulate matter.
Method Description
Highly purified recombinant hepatitis E virus (HEV) antigens (O2N, O2C, and O3 from genotypes 1 and 3, and O2M from genotype 1) are fixed to nitrocellulose membrane test strips. The test strips are incubated with the diluted patient serum sample, allowing virus-specific human IgM antibodies to bind to the antigens present on the test strips. Unbound human antibodies are then washed away. In the second step, the strips are incubated with anti-human IgM antibodies coupled with horseradish peroxidase enzyme. Unbound conjugate antibodies are then washed away. Specifically bound human IgM antibodies are detected with a staining reaction catalyzed by the peroxidase. A dark band will appear on the strip at the corresponding point if a reaction has taken place.(Package insert: recomLine HEV IgG/IgM kit. Mikrogen Diagnostik; rev 10/2014)