MLT-125 Exam 2 Flashcards
What is the best temperature range for cold agglutinins to develop?
0-5 degrees C
Give 3 examples of infections that may cause cold agglutinins to develop.
Mycoplasma pneumoniae
IM
Primary atypical pneumoniae
Small quantities of Ag is injected in hypersensitive pt at closely spaced intervals to help build tolerance to an ordinarily shocking dose w/o severe rxn.
desensitization
Briefly explain Grave’s disease
increased T3 and T4 and decreased or absent TSH(thyroid stimulating hormone); goiter, weight loss, tachycardia
Explain what the reactions mean in a hemagglutination inhibition test
= agglutination
+ lack of agglutination; pt AB present
Within which organ is it thought that potentially self-reactive lymphocytes are removed?
Thymus
The Nichols strain of T. pallidum is used in what type of testing?
FTA-ABS
When do serum tests for syphilis usually become reactive?
primary chancre; 1st and 3rd weeks
In secondary syphilis, would the serological tests performed to detect syphilis be +, =, have no diagnostic value, or are they not performed in that stage? How long after treatment does the serological test become nonreactive?
Serological tests are +
12 months
The secondary stage of syphilis occurs how many weeks after the appearance of the primary chancre?
6-8 weeks
Name the three pharmacologically active mediators of anaphylaxis
Histamines
Eosinophil Chemotactic Factors of Anaphylaxis(ECF-A)
Proteolytic enzymes(tryptase,chymase)
What stage of syphilis is usually noncontagious?
Latent stage
P24 is a viral antigen that is the first to be detected in which potentially deadly virus?
HIV
Name three means of transmission of the HIV virus?
intimate sexual contact
contact with blood or body fluids
perinatally from infected mother to infant
Needles that dispense antigen for the VDRL test must be calibrated to deliver how much? How often should the needle be QC’d?
1/60 of a mL
each time test is performed
T. pallidum crosses the placents in which week of gestation?
18th
What does the FTA-ABS test identify in the patient’s serum? What does the fluorescein labeled antihuman globulin do for the purposes of interpreting this test?
identifies treponemal Ab
makes Ag-Ab rxn visible
In the direct fluorescent antibody test, the____ is “labeled” with fluorescent dye.
Antibody
The serum is inactivated to destroy complement in the VDRL or RPR?
VDRL
Give 5 examples of an autoimmune disease and describe whether it is organ-specific and, if so, which organs are affected or if it is systemic.
Addisons - organ; adrenal glands MS - organ; myelin sheaths on nerves Lupus - systemic; skin, joints, kidney, brain, heart, lungs RA - both- joints, lungs, skin Grave's - organ; thyriod
A flat bottomed bottle is required in the VDRL or RPR?
VDRL
Explain a flocculation test and give examples of this type of testing.
a very specific type of precipitation that occurs over a narrow range of antigen concentration; RPR VDRL
The VDRL or the RPR is always read macroscopically?
RPR
A modified VDRL antigen is used in what type of testing?
RPR
Name some synonyms for Type B viral hepatitis.
serum hepatitis
Hep B
HBV
The initial primary lesion that develops on the external genitalia in syphilis.
Chancre
The rotator speed for RPR should be ___rpm?
100 rpm; 180 rpm on VDRL
Why do you get false negative results with a postzone reaction?
excess Ag; may obscure the presence of a small amount of Ab
The antibody to tissue lipids is called ___?
reagin
Why would you get false negative results with a prozone reaction?
Ab excess; not enough Ag to cause precipitation
Ag and Ab are precipitated to a maximum; number of multivalent sites of Ag and Ab are aprox. equal. Reversible reactions where Ab bind with more than on Ag and vice versa, forming lattice.
Zone of equivalence
What is tannic acid used for in serological testing?
allows proteins to complex with RBC as antigen carriers
Type III hypersensitivity reaction that results from the buildup of Ab to animal serum used in passive immunization.
Serum sickness
How does the Western blot test differ from ELISA tests?
ELISA is a screening test that identifies any Ab to HIV
Western blot identifies specific Ag for confirmatory testing
An Ab that causes clumping or agglutination of the cells that triggered its formation.
Agglutinin
Why is cholesterol added to the antigen that is used in the flocculation test for syphilis?
center of absorption for tissue lipids; so agglutinated particles can be visualized
T or F Treating a pregnant woman with syphilis does not cure the fetus.
False; can cure fetus
T or F Congential, primary and secondary syphilis are best treated by repeated doses of penicillin.
False; single shot
T or F Treatment does not alter any tissue damage that has already occurred.
True
T or F It is necessary to get repeated blood tests for 5 years following treatment.
False
T or F Tertiary syphilis cannot be treated.
False
Loss of self tolerance results in what type of disease?
Autoimmune
Explain cross reactivity and what kind of results it can lead to.
Ag that are closely related in structure can provide false positive results
The presence of anti-double stranded DNA can distinguish RA from what other autoimmune disease?
Lupus
Combining soluble Ag with soluble Ab to produce insoluble complexes that are visible.
Precipitation
Recent experiences or exposure to group A hemolytic Strep can be detected when there are high or steadily increasing concentrations of what in a patient’s serum?
anti-streptolysin-O
A life threatening response to an allergen characterized by the systemic release of histamine.
Anaphylaxis
What is a xenograft? Also know as what?
heterograft; the transfer of tissue from an individual of one species to an individual of another species
Transplanting from one individual to a genetically nonidentical person of the same species is called what?
Allograft or Homograft
A delayed hypersensitivity reaction caused by T-cell sensitization to low molecular weight compounds; such as nickel and rubber, that come into contact with the skin
Exposure to metals, antibiotics, dyes, poison ivy
Contact dermatitis
Which type of test is most widely used to detect HIV?
ELISA
Which hepatitis is the most virulent? Why is Hep C more dangerous than Hep B?
Hep C
85% of Hep C infected develop chronic infection, only 10% in Hep B infected
2 out of 3 infected become carriers that can transmit
What is the first antigen to appear in the serum of a person infected with HBV?
HBsAg
How is Hepatitis A transmitted?
fecal-oral route
The only Hypersensitiity Type that involves T-Cells?
Type IV hypersensitivity
T or F Testing for the p24 antigen would be useful as a screening test for blood products?
False
On average, it takes __to__ weeks for an individual to develop antibodies after exposure to HIV?
6 to 12
What antibody appears in the serum of individuals that have recovered from Hepatitis B or who have received the Hepatitis B vaccinations?
HBsAg
Anti-HBsAg
Which form of Hepatitis is responsible for the most post-transfusion reactions?
Hep C
If a patient has an immune response to his/her own IgG, they would most likely have a positive or negative RA test?
Positive +
*IgG is in RA
IgM is in RF
Which set of antigens would be represented on a positive Western blot?
gp41 and gp120
The antigen in a precipitin reaction must be _____?
soluble
What does ANA stand for? How is testing for this useful?
Antinuclear Antibody
found in 95% of lupus patients
What does HLA stand for and why is it important?
Human Leukocyte Antigen
for survival of transplant tissue and organs
Which hepatitis virus requires HBV infection?
Hep D
When discussing EBV and infectious mono, name the primary mode of transmission. What % of lymphs would you expect to see as atypical on a peripheral blood smear? Which malignancy has been associated with EBV?
salivary secretions
10%
Burkitt’s lymphoma, Hodgkins disease
Which virus have most people been exposed to by their elderly years?
CMV - cytomegalovirus
Name some examples of antiretroviral drug therapies. How do they work?
Nucleoside analogue reverse transcriptase inhibitors
Nonnucleoside reverse transcriptase inhibitors
Protease inhibitors
Fusion inhibitors
Coreceptor antagonist and integrase inhibitors
By blocking various steps of virus replication
Which cells are the main target for the HIV virus? Why?
T-cells
high number of CD4 antigen - serves as a receptor for the virus
What is one method for determining the progression to the AIDS stage of HIV infection. How is this done (the gold standard)?
CD4 T-cell enumeration of less than 200 uL
Gold standard for testing is Flow Cytometry
Shingles is essentially a re-emergence of what virus?
VZV - Varicella-Zoster Virus; chicken pox
Regarding HIV transmission, which specimens are not considered infectious unless visibly blood?
Saliva Sputum Nasal secretions Tears Sweat Urine Vomitus Feces
In the HIV virus, what is reverse transcriptase responsible for doing? Name the gene that codes for the enzymes necessary for HIV replication.
Transcribes viral RNA into DNA
pol gene; namely p66 and p51
Briefly describe the latency period of HIV infection. What is the median length of time this can last?
decrease in viremia
clinical symptoms are subtle or absent
gradual deterioration of immune system
Median length of approx 10 years
Symptoms of primary infection of HIV are similar to symptoms from what other virus?
Infectious Mono; fever, lymphadenopathy, sore throat, myalgia, fatigue, weight loss…
List the advantages and disadvantages of chemiluminescent assays
ADVANTAGES:
Excellent sensitivity
Reagents are stable and relatively nontoxic
Inexpensive
Faster turnaround time
DISADVANTAGES:
False results possible from lack of precision in injection of the hydrogen peroxide
Urine and plasma may cause quenching of the light emission
Measure of cloudiness of a solution; measures reduction of light intensity due to reflection, scatter and absorption
Turbidimetry
Measures light that is scattered at a particular angle from the incident beam as it passes through a suspension.
Nephlometry
The antibody that is rheumatoid factor belongs to which Ig class?
IgM
What is the test anti-CCP and what is it used for?
CCP - Cyclic citrillunated peptide
lead marker for RA, more sensitive than RF
RPR
Rapid Plasma Reagin
VDRL
Venereal Disease Research Laboratory
Radiation
Chemicals
Viruses
Disease processes
5-10% of acute cases progress to chronic infection
1/3 of chronic infections have high risk of chronic active hepatitis, liver cirrhosis &/or liver cancer
Causative agents of Hepatitis
