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Virology22-2-11
Diagnostic methods in virology
Detection of virus
Detection of viral antigen
Detection of viral genome
Detection of serological response
Detection of viral antigensAntisera (mono or polyclonal) are used to
detect viral antigen
These assays can be sensitive as they can detect antigens of disrupted viral particles
They are pathogen specific - separate immuno-assay must be used for each pathogen
In contrast electron microscopy and culture are catch all techniques which detect all pathogens
MethodsAntigen capture ELISA - eg rotavirus, HBsAg, HIV
Latex particle agglutination (LPA) eg rotavirus
Immunoflouresence - eg RSV, influenza,
Viral antigen detection: ELISA for rotavirus
ELISA for Hep C antibody
Virus antigen detection: Latex particle agglutination for rotavirus
Virus antigen detection: Immunofluorescence - direct
Virus antigen detection: Immunofluorescence of RSV-infected
nasopharyngeal cells
Detection of viral genome
Genome amplification eg. PCR (polymerase chain reaction)
Viral genome detection: qPCR
Viral genome detection: PCR
Detection of serological responseIgM detection
Detection of rising titre: ELISA, complement fixation test, haemagglutination inhibition
Detection of serological response: Antigen capture ELISA for HIV
antibody
Case 1The following is a report from a lady with a
10-year history of fatigue, anorexia and elevated LFTs.
Hepatitis B surface antigen: negative
Hepatitis C antibody: positive
Hepatitis C antibody immunoblot confirmation: positive Banding pattern: c100 c33 c22 NS5
3+ 3+ 4+4+
Case 1What additional tests would you request?
What your treatment options
Case 2You are given the following results on two
different patients.
Are there any differences between the profiles?
What implications (if any) are there for these differences?
Case 2
Patient 1:
Tests Results
EIA for HBsAg Positive
***Infection Risk***
Hepatitis B e antigen Negative
Hepatitis B e antibody Positive
Hepatitis B core IgM antibody Negative
Report comment: Hepatitis B result profile consistent with
chronic hepatitis B infection.
Case 2Patient 2:
Tests Results
EIA for HBsAg Positive
***Infection Risk***
Hepatitis B e antigen Positive
***High Infection Risk***
Hepatitis B e antibody Negative
Hepatitis B core IgM antibody Positive: 250 IU/ml.
Report comment: Hepatitis B result profile consistent with
chronic hepatitis B infection.
Case 2
Do you agree with the comments?
What additional test(s) would you request for after a discussion with the microbiologist?
Case 3
You have vaccinated 2 patients against hepatitis B virus for the purpose of foreign travel.
What test would you request to assess the vaccination status?
Comment on the following results.
Case 3
Patient 1:
Hepatits B surface antibody: >1000 mIU/ml
Patient 2:
Hepatitis B surface antibody: <10 mIU/ml
Case 4A patient presents with malaise, elevated
LFTs and a history of intravenous drug abuse. You are given the following result:
Hepatitis B surface antigen: Positive
Hepatitis B surface antibody: Negative
Report comment: If this is the first positive serological test on this patient, please repeat to confirm.
Case 4
Comment on the above report.
What additional tests would you request?
Case 4
Hepatitis B surface antigen: Positive
***Infection Risk***
Hepatitis B e antigen: Positive
***High Infection Risk***
Hepatitis B e antibody: Negative
Hepatitis B core IgM antibody: Negative
Hepatitis B core total antibody: Positive
Report comment: ………..
What is your report comment?
Case 5A 23 year old female patient presents to the A/E
department with malaise, lymphadenopathy, malaise and a rash. She has a history of unsafe sexual activity.
What investigations would you request?
Case 5Shown below is one of the patient’s
laboratory results:
Tests Results
EIA for anti-HIV 1 (Organon) Positive
EIA for anti-HIV 1+2 (Murex) Positive
Report comment: ***confirmed anti-HIV 1 positive***
What additional tests would you require?
What would you advise the patient?