Immunology and Serology Flashcards
7 cards from real Medical Technologist Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Immunology and Serology flashcards as text
Which hepatitis B serological marker is the FIRST to appear in serum during acute infection?
Answer: HBsAg
HBsAg (hepatitis B surface antigen) is the earliest detectable marker in serum, appearing during the incubation period before clinical symptoms.
The RPR (Rapid Plasma Reagin) test for syphilis uses which antigen?
Answer: Cardiolipin-lecithin-cholesterol
The RPR is a nontreponemal test using a cardiolipin-lecithin-cholesterol antigen to detect reagin antibodies produced during syphilis infection.
The prozone phenomenon in serology results in a false-negative reaction due to:
Answer: Antibody excess preventing lattice formation
Prozone occurs when antibody greatly exceeds antigen, saturating all antigen binding sites and preventing the cross-linking necessary for a visible reaction.
Which test is used as a CONFIRMATORY assay for HIV infection following a reactive screening result?
Answer: Western blot
Western blot identifies antibodies against specific HIV proteins (e.g., gp120, gp41, p24) separated by molecular weight and serves as the confirmatory test.
C-reactive protein (CRP) is produced primarily by which organ during the acute phase response?
Answer: Liver
CRP is an acute phase protein synthesized by hepatocytes in the liver in response to IL-6 released during inflammation or infection.
The Weil-Felix test uses Proteus OX antigen strains to diagnose infections caused by:
Answer: Rickettsia species
Weil-Felix exploits cross-reactive antigens shared between certain Rickettsia species and Proteus OX2, OX19, and OXK strains to detect rickettsial infections.
Which complement component is shared by ALL three activation pathways (classical, alternative, and lectin)?
Answer: C3
C3 is the central convergence point of all three complement pathways; its cleavage to C3a and C3b is the pivotal step in complement activation.