BOC study part 4
The volume of urine recommended for centrifugation for a microscopic examination is:
10 - 15 mL
What is the half-life of IgG? Why is the duration of the half-life significant?
18-23 days; it binds with neonatal Fc receptor.
Absorbance (A) of a solution may be derived from percent transmittance using which formula?
2- log%T
When transporting donated platelet units, what is the maximum amount of time that agitation of platelets can be stopped for?
24 hours
What is the lower reference limit for progressive motility of spermatozoa when performing a semen analysis?
32%
How is beta thalassemia defined?
A decrease in the rate of production of beta chains due to a partial or total deletion of loci from chromosome 11 that code for the beta chain.
Which of the following statements regarding the ABO phenotype A2 is true?
A2 antigens are linear while A1 antigens are branched.
Trypanosoma cruzi is the etiologic agent of:
Chagas' disease
Which of the following action describes the MAJOR property of antidiuretic hormone?
Changes distal tubule water permeability
A small child has albino characteristics, photophobia, frequent pyogenic infections, and her blood smear shows giant dark granules in her monocytes and granulocytes. What is the probable diagnosis?
Chediak-Hegashi syndrome
lipid tests is LEAST affected by the fasting status of the patient?
Cholesterol
Which complement pathway and a related initiator can activate complement?
Classic pathway; antigen-IgG antibody complexes
What organism is responsible for a potentially lethal type of food poisoning caused by improperly canned food?
Clostridium botulinum
Which of the following organisms is most likely to be associated with gas gangrene:
Clostridium perfringens
Bruton's agammaglobulinemia is a:
Congenital B-cell disorder
Ionized calcium is currently most commonly measured using which of the following method?
Calcium ion selective electrodes
methodology measures the amount of electricity passing between two electrodes?
Coulometry
What should be done if all forward and reverse ABO results are NEGATIVE?
Incubate at room temperature or 4°C to enhance weak expression.
Which of the following choices is the basic technique used to detect unexpected antibodies with a commercial set of reagent cells?
Indirect antiglobulin test
Which of the following can cause a false positive result for ketones?
L-Dopa metabolites
In a normal CSF the protein concentration as compared to that in the plasma is generally:
Less than 1%
Which of the following stains is used to differentiate a neutrophilic leukemoid reaction from chronic myelogenous leukemia (CML)?
Leukocyte alkaline phosphatase (LAP)
Nephelometry involves the measurement of:
Light scatter
Which of the following is considered the major transport protein for vitamin A?
Retinol-binding protein
What is the characteristic RBC that is uniquely associated with HbSS?
Sickle cell (drepanocyte)
Removal of which of these organs may be a last resort treatment for a patient whose platelet count is less than 30 x 109/L as a result of chronic idiopathic thrombocytopenic purpura (ITP)?
Spleen
What type of graph is needed in a real-time PCR in order to perform absolute quantification?
Standard curve
The fibrinolytic system may be activated by
Streptokinase
The estimation of hyaluronic acid concentration by measurement of viscosity is useful in evaluating which type of fluid?
Synovial
What is the half-life of digoxin in plasma?
38 hours
A laboratory professional is going to perform a mixing study to differentiate between a factor deficiency and a coagulation inhibitor as the cause of a prolonged prothrombin time (PT) or activated partial thromboplastin time (aPTT) test result. The mixing study should be performed within what time frame following collection of the specimen?
4 hours
How long does it take for plasma concentrations to reach steady state when a patient's dose is given at intervals of the drug's half-life?
5-7 half-lives
What is the maximum number of white blood cells that may be present in 95% apheresis platelet units that have been leukocyte-reduced?
5.0 x 106
A platelet component prepared from a unit of whole blood (random donor platelet) must contain at least how many platelets?
5.5 x 1010 platelets/unit
If an Rh group (DCe/dce) man marries an Rh group (dce/dce) woman, what is the probability that their first child will be D negative?
50%
In heme synthesis, how many molecules of delta-aminolevulinic acid (ALA) are needed to form one molecule of heme?
8
When should a peak digoxin level be drawn?
8-10 hours after an oral dose
A unit of leukocyte-reduced red blood cells must retain at least what percentage of red blood cells following leukoreduction?
85%
Which of the following would be considered a normal cerebrospinal fluid glucose level if the serum glucose is 70 mg/dL?
About 45 mg/dL
ß-hydroxybutyric acid is formed as the result of an accumulation of which of the following?
Acetyl-CoA
What form of immunity is expected to provide long-term protection after hepatitis B vaccine (HBV) is administered to an immunocompetent person?
Active
Fifty percent blasts are found on a peripheral blood smear. The cells are large (3-5x the size of a lymphocyte) with a nucleus that contains homogeneous fine chromatin and two to three nucleoli. There is moderate blue-grey cytoplasm with Auer rods. What leukemia is most likely?
Acute myelogenous leukemia (AML)
Uric acid is the final breakdown product of what two purines?
Adenine and guanine
The reagent strip method for protein primarily tests for which type of protein?
Albumin
usually shows a decrease during an acute phase response?
Albumin
Which of the following blood tests is used to determine acute pancreatitis?
Amylase
Hormonal variation throughout the menstrual cycle typically shows:
An abrupt rise in luteinizing hormone (LH) 3-36 hours prior to ovulation
Which antibody is present in the blood of an individual with the Bombay phenotype that will cause agglutination with any non-Bombay individual's blood?
Anti-H
Which of the following markers would you expect to find in the serum of a patient who has recently recovered from Hepatitis B infection?
Anti-HBs
Which risk marker has both positive and negative cardiovascular risk integrated into its measurement?
Apo B-100/Apo A-1
A physician needs to prescribe a drug to a patient but the drug has a narrow therapeutic window. He is concerned about possible toxic effects. To assess the upper concentration of such a drug, which time for drawing the specimen do you think makes the most sense?
Approximately one hour after an oral dose
Which assay is performed to diagnose congestive heart failure (CHF)?
B-type natriuretic peptide (BNP)
Which of the following tests should be collected in serum gel tube and goes to the chemistry department?
BUN
Which disease/condition is associated with a deficiency in thiamine?
Beriberi
Cooley's anemia is another name for which form of beta thalassemia?
Beta thalassemia major
Which beta thalassemia shows no anemia and may not be detected using hemoglobin electrophoresis?
Beta thalassemia minima
A tissue sample is received in the laboratory for fungal culture. How should the tech prepare the sample for inoculation onto agar plates?
Cut/Mince tissue into small pieces with sterile scissors
A low-incidence antigen is one that occurs in less than 10% of the population. Which of the following is a low-incidence antigen?
Cw
Which of the following laboratory test results indicates that a sickle cell patient may be in aplastic crisis?
Decreased reticulocyte count
When evaluating a patient for a suspected Wilson's Disease diagnosis, low values of plasma ceruloplasmin would be expected along with:
Decreased serum copper
In patients with suspected primary hypothyroidism associated with Hashimoto's thyroiditis, one would expect the following laboratory test results:T4 ___? TSH ___? TRH stimulation ___?
Decreased, increased, increased
An example of a laboratory test that can be performed and interpreted by individuals who are not trained laboratory personnel is:
Dipstick urinalysis
Elevation of serum creatine kinase may be associated with:
Duschenne muscular dystrophy or cerebrovascular accident (stroke) or vigorous exercise.
For the diagnosis of Systemic Lupus Erythematosus (SLE) which of the following test principles provides the highest specificity?
ELISA
The diagnostic stage for helminths is:
Egg
The function of the very low density lipoproteins (VLDL) is to transport:
Endogenous triglycerides
Although it is actually non-motile, which Gram-positive, catalase-negative organism produces "bottle brush" growth from the stab inocuation in a gelatin agar tube at 22° C, along with hydrogen sulfide production in TSI agar?
Erysipelothrix rhusiopathiae
Ninety-nine percent of lead absorbed in the body is taken up by what after absorption?
Erythrocytes
Recently the American Diabetes Association (ADA) recommended reporting which of these values to correlate with hemoglobin A1C (HbA1C) as a further indicator of glycemic control?
Estimated average glucose
What additional fraction would be seen if plasma rather than serum was subjected to electrophoresis:
Fibrinogen
found in plasma but absent in serum?
Fibrinogen
Which type of kinetic reactions are reactions in which the enzyme is in excess and the substrate concentration is the limiting factor?
First order
What is the ultimate goal of secondary hemostasis?
Formation of a fibrin clot
Coombs control check cells used to verify negative reactions at the anti-globulin (IAT) phase are coated with:
IgG antibodies
A primary immune response typically presents with which class of antibody?
IgM
Which enzyme is responsible for the conjugation of bilirubin?
Glucuronyl transferase
Many red blood cell (RBC) processes, such as binding, transporting, and releasing oxygen, do NOT require energy. Energy however, is required for cellular viability. How does the RBC obtain most of it's energy?
Glycolytic pathways
A positive CAMP reaction and hippurate hydrolysis are key in identifying which beta-hemolytic streptococci?
Group B
The antigen marker most closely associated with transmission of HBV infections
HBeAg
Which of the following tests has been recommended by the FDA to replace the HIV-1 p24 antigen test in the screening of donated blood for infectious diseases?
HIV-1 NAT
Which type of antibodies are known to cause transfusion-related acute lung injury (TRALI) reactions?
HLA antibodies
The accuracy of an immunoassay is its ability to discriminate between results that are true positive and results that are true negative. Two parameters of test accuracy are specificity and sensitivity. Which of these statements apply to an immunoassay with low sensitivity?
Has many false-negative results
The area of suppressed growth surrounding a disk impregnated with an antimicrobial on a sensitivity plate is referred to as the zone of:
Inhibition
What is the function of LD in the body?
Interconversion of lactate and pyruvate
What is the most significant cause of decreased haptoglobin levels?
Intravascular hemolysis
Which coagulation pathway is initiated when collagen is exposed, and involves the substances high-molecular-weight kininogen (HK), prekallikrein (PK), and factor XII?
Intrinsic
Which of the following is necessary for the absorption of Vitamin B12:
Intrinsic factor
Which of the following methods would be employed to collect sweat for chloride analysis:
Iontophoresis
In theory, how difficult is it to find a compatible blood unit and to identify the antibody in a patient with an antibody to a low-frequency antigen, such as Kpa or Jsa?
It is not difficult to find compatible blood but difficult to identify the antibody
high frequency antigen
Lub
cells would be increased if the cerebrospinal fluid (CSF) of a patient suspected of having multiple sclerosis?
Lymphocytes
responsible for causing transfusion associated graft-versus-host disease?
Lymphocytes
What are the two polypeptide chains that comprise the LD molecule?
M and H
When assessing a bone marrow aspirate smear of an adult, a normal M/E ratio (myeloid to erythroid cells) would be?
M:E = 2.5:1
How does RhIg prevent anti-D production?
Mainly by suppressing the immune response after exposure to D positive cells.
Which specific immunodominant sugar is responsible for A (blood group A) antigenic specificity?
N-acetyl-D-galactosamine
Aminoglycosides can cause severe toxicity including
Nephrotoxicity and ototoxicity
A patient front-grouped as AB but back-grouped as O. The screening cells and auto control were positive. If the testing was performed correctly, what is the most likely cause of this discrepancy?
Patient has a cold autoantibody
Components of the second line of defense in the human body are:
Phagocytic cells; complement
Which of the following tests would be most affected by microclots in an EDTA tube drawn for a CBC?
Platelet count
tests is expected to have a normal result in a patient with type 1 von Willebrand disease?
Platelet count
Immunocompromised patients, such as those with Acquired Immunodeficiency Syndrome (AIDS) are at an increased risk of contracting an unusual form of pneumonia from which of the following microorganisms?
Pneumocystis jiroveci (carinii)
A false-positive result can be observed in a rheumatoid factor latex agglutination procedure reaction due to:
Poor specimen quality
Which finding best distinguishes immune hemolytic anemia from other hemolytic anemias?
Positive DAT
A patient is experiencing prolonged bleeding following a transfusion. The complete blood count indicates that the patient's platelet count has decreased following the transfusion. What is the most likely cause of this issue?
Posttransfusion purpura
Hyperacute rejection of a transplanted organ is caused by:
Pre-formed humoral antibodies in a patient
Rothia mucilaginosus is a member of the family Micrococcaceae that has been associated with endocarditis in patients after cardiac catheterization, as well as intravenous drug users. Which test listed below would be most helpful in making a species identification?
Presence of a capsule
A solution of gamma globulins containing anti-Rh(D) is given to an Rh(D) negative mother to:
Prevent fetal cells from initially sensitizing the mother
The MOST accurate observation about osmotic pressure is that it is:
Proportional to concentration of solute particles
Which of the following is responsible for inhibiting the tissue plasminogen activator?
Protein C
Sodium thiosulfate is often added to selective culture media to:
Provide sulfur atoms for H2S positive isolates
In an adult, hematopoiesis occurs in which of the following listed sites?
Proximal ends of long bones
What is the principle of the Kleihauer-Betke test?
The Kleihauer-Betke test capitalizes on the resistance of fetal hemoglobin to acid treatment.
goal of primary hemostasis.
The formation of a platelet plug
Why is it dangerous to transfuse a blood group O person with a unit of blood group A?
The patient's anti-A would destroy the donor's cells with severe consequences to the patient.
What conclusion can be made if a person has a cardiovascular risk marker that is abnormal?
The person has an increased probability of developing cardiovascular disease.
When giving a whole blood donation to a patient, what consideration must be made in regards to the ABO/Rh compatibility between the recipient and the donor?
The recipient and donor ABO and Rh types must be identical.
Pappenheimer bodies (or siderotic granules) in erythrocytes can be detected using the following stain/s.
Wright's stain and Prussian blue stain
How long should therapy continue for patients with hereditary hemochromatosis (HH)?
Therapy should continue throughout the lifetime.
Which of the following converts Fibrinogen into Fibrin Monomer?
Thrombin
characteristic of Francisella tularensis?
Tiny, weak-staining, gram-negative coccobacilli
What are the 3 main effects of active vitamin D on the body?
To absorb calcium and phosphorus in the intestines, from bone, and in the kidneys
Which of the following infections is caused by Chlamydia trachomatis?
Trachoma, a major cause of preventable blindness in the world.
Which of the following is true of the classic Bombay phenotype?
Two h genes are inherited at the H locus
To produce hemoglobin S (HbS), glutamic acid that is normally present in the sixth position on the beta globin chain is substituted with
Valine
A deficiency in which of the folowing vitamins is associated with "scurvy"?
Vitamin C
Which organism is MOST likely responsible for septic reactions associated with red blood cell transfusions?
Yersinia enterocolitica
Which one of the following tests BEST correlates with the severity of hemolytic disease of the fetus and newborn (HDFN)?
color Doppler ultrasonography
Peak level is the point at which the drug is
highest in the patient's body.
