General Flashcards
1
Q
At a pH of 8.6 the gamma globulins move to the cathode, despite the fact they are negatively charged. What is this phenomenon called?
A
Endosmosis
2
Q
What is cleaved as a result of the activation of the classical complement pathway?
A
C4
3
Q
A sample of blood from each donation is tested for which infectious disease agents?
A
HIV-1/2, HTLV-I/II, WNV, HCV
(Also tested for HBV, syphilis, and if regionally relevant Babesia)
4
Q
A kleihauer-betke stain of postpartum blood film revealed 0.3% fetal cells. What is the estimated volume (mL) of the fetomaternal hemorrhage expressed as whole blood?
A
15mL = 0.3% x 50mL
5
Q
In a random population 16% are Rh negative (rr), what percentage of the Rh positive population is heterozygous for r?
A
48%
Hardy-Weinberg: p²+2pq+q²=1.0
6
Q
Shigella species are characteristically
A
Nonmotile
7
Q
Arterial thrombosis is caused by
A
WBC & platelets
8
Q
The enzyme responsible for conferring H activity on the RBC membrane is alpha-
A
L-fucosyl transferase (genetic product of H gene, confers H antigen specificity by adding fucose to terminal galactose)
9
Q
Low volume CSF produces 1mL in a single tube, what test should be performed first?
A
Gram stain & culture, preserving sterility. Then cell count, then chemistries
10
Q
In the liver, bilirubin is converted to:
A
Bilirubin diglucuronide
11
Q
Single test that could reliably detect neonatal infection in absence of clinical signs
A
Quantitative serum IgM determination
12
Q
HLA allele classical associated w/ ankylosing spondylitis is:
A
HLA-B27
13
Q
Small protozoan cysts are found in a wet mount of sediment from ethyl-acetate concentrated material. Each cyst has 4 nuclei that do not have peripheral chromatin, each nucleus has a large karyosome which appears as a refractive dot. These are most likely:
A
Endolimax nana
14
Q
What is the characteristic second stage of Borellia burgdorferi infection?
A
Spread to multiple organ systems via bloodstream.
1st stage lasts 3-6 wks & without treatment may lead to neurological or cardiac involvement in second stage
15
Q
TSH is produced by the:
A
Pituitary gland
16
Q
An electrophoretic separation of LDH isoenzymes that demonstrates an elevation in LD1 and LD2 in a flipped pattern is consistent with:
A
Myocardial infarction
Healthy: 29-39% LD2, 14-26% LD1, ratio 0.45-0.74
17
Q
Hereditary deficiency of late complement components (C5, C6, C7, C8) can be associated with what condition?
A
Systemic Neisseria infection, if exposed (due to reduced pathogen clearance)
18
Q
Sputum sample has the following characteristics:
-growth at 6 days on BCYE in CO2 at 35C
-delicate branching GPR
-branching, filamentous, partially acid fast
A
Nocardia
19
Q
Talaromyces (formerly Penicillium) spp can be differentiated from Aspergillus fumigatus by:
A
Lack of vesicle at end of conidiophore
20
Q
Low prevalence antigen?
A
Wrª
21
Q
What is the recommended confirmatory test for an unknown mold suspected of being a pathogenic dimorphic fungi?
A
Molecular testing (conversion from mold to yeast may take several days)
22
Q
What anomaly us an autosomal dominant disorder characterized by irregularly sized inclusions in PMN, giant abnormal platelets, and often thrombocytopenia
A
May-Hegglin, inclusions may resemble Döhle bodies
23
Q
Most frequent cause of prosthetic heart valve infection within 2-3 months of surgery is:
A
Staphylococcus epidermidis
24
Q
Amniotic fluid may be tested to determine the concentration of lamellar bodies to evaluate for:
A
Fetal lung maturity
25
Which serum protein fraction is most likely to be emevated in patients with nephrotic syndrome?
alpha-2 globulin & beta globulin (d/t loss of albumin, increased a-2 globukin is a compensation mechanism)
26
What are the calculated RBC parameters on an automated hematology analyzer?
Hct (mcv, rbc)
MCH (hgb, rbc)
MCHC (hgb, hct)
27
Pellagra is associated with deficiency of which vitamin?
Niacin, also associated with chronic alcoholism
28
60 yr old female patient presents w/ blurred vision, confusion, fever, severe bruising, and plt count of 29
PT: 12.1s (ref 11.4-13.5s)
aPTT: 32.6s (ref 25-36s)
RBC morphology shows schistocytes, differential Dx should include:
TTP: characterized by triad of macroangiopathic hemolytic anemia, thrombocytopenia, neurological abnormalities. Fever, renal dysfunction often present. PT, aPTT normal
29
What is most closely associated with iron deficiency anemia?
Chronic blood loss
30
What cell surface marker is associated with a more aggressive subtype of CLL/SLL?
CD38
31
What clinical presentation is associated with HHV8 (human herpesvirus 8)?
Kaposi's sarcoma, especially in immunocompromised patients
32
Alloantibodies are found in what form of hemophilia?
Congenital hemophilia, in response to treatment with donor factors
33
A myeloperoxidase stain & immunophenotyping are performed on bone marrow smears from pt w/ acute leukemia.
Myeloperoxidase +, immunophenotyping shows CD4, CD11b, CD13, CD64.
What type of leukemia is indicated?
Myelomonocytic
34
What phenotypes arise from the different Rh genes?
R1: DCe
R2: DcE
R0: Dce
Rz: DCE
r'dCe
r'': dcE
r: dce
ry: dCE
35
Branching gram positive, partially acid fast organism isolated from bronchial wash of 63yo receiving chemo. Does **not** hydrolyze casein, tyrosine, or xanthine. Most likely genus is:
Nocardia
36
What organism is the most common anaerobic bacteria isolated from infectious processes of soft tissue & anaerobic bacteremia?
Bacteroides fragilis
37
An electrode as a silver/silver chloride anode & a platinum wire cathode. It is suspended in KCl solution & separated from the blood to be analyzed by a selectively permeable membrane. What is it measuring?
pO2
38
Gram stain of a blood culture bottle shows GPC in clusters, growth on BA & CNA show small, round, pale yellow colonies. Further tests include:
Catalase production, protein A agglutination (staph latex)
39
A patient is being worked up for lupus anticoagulant. DRVV screen is prolonged at 75s w/ normal pooled plasma at 35 s. DRVV confirm is 38 s w/ pooled normal at 36s. What is the normalized ratio?
2.03
(Screen/PNP)/(confirm/pnp) = normalized ratio
40
68yo F, cold all the time, recent weight gain. TSH 8.7 (ref 0.5-5). Most likely has:
Primary *hypo*thyroidism
41
Prep for standard glucose tolerance test should be:
High carb diet for 3 days
42
If a fasting glucose is 90mg/dL, what would be a normal 2hr post-prandial glucose?
100 mg/dL
43
Healthy person with glucose of 80mg/dL would have a csf glucose of:
50 mg/dL
(normal ratio: 0.6, low in bacterial meningitis & elevated in viral meningitis)
44
Patient vomited 90 minutes after receiving standard 75g carbohydrate dose for oral glucose tolerance test. Best course of action is to:
Draw blood for glucose & discontinue test
45
Serum levels that define hypoglycemia in pre-term or low birth weight infants are:
Lower than adults
46
In the fasting state, arterial & capillary blood glucose varies from venous concentration by approximately:
+5mg/dL
47
Fasting plasma glucose of 126mg/dL is diagnostic for:
Diabetes mellitus
48
Glycerated hemoglobin value represents the integrated values of glucose concentration during the preceeding:
6-8 weeks
49
A patient with type 1 diabetes has a fasting blood glucose of 150 mg/dL, hemoglobin A1c of 8.5%, and fructosamine of 2.5 mmol/L. What state of metabolic control is the patient in?
(Glucose: 70-110mg/dL, A1c: 4.0-6.0%, fructosamine: 2.0-2.9 mmmol/L)
Improving state of metabolic control, indicated by fructosamine
50
Total glycosylated hgb levels in hemolysate reflect the:
Average blood glucose of the past 2-3 months
51
A patient with hemolytic anemia will demonstrate what change in glycated hgb values?
Decrease, directly related to RBC lifespan
52
Infant with diarrhea is being evaluated for carbohydrate intolerance. Stool yields a positive copper reduction test & pH of 5.0. What conclusions can be made?
None, further testing is required b/c copper reduction test detects many reducing agents
53
Blood samples were collected before & after a 30 minute aerobics class. What lactic avid & pyruvate levels are expected in the post-class samples?
Elevated lactic acid, elevated pyruvate
54
What is the best method to diagnose lactase deficiency?
H2 breath
55
Blood gasses for a patient in chronic renal failure would match the pattern of:
Metabolic acidosis
56
Severe diarrhea causes what blood gas pattern?
Metabolic acidosis
57
At blood pH of 7.40, what is the ratio of bicarbonate to carbonic acid
20:1 (ratio at normal pH)
58
Patient admitted in metabolic alkalosis, what TCO2/HCO3 results are expected?
High TCO2, increased HCO3
59
What blood gas abnormalities are expected in a patient with metabolic alkalosis?
Elevated CO2, pH
60
Metabolic acidosis is described as:
A decrease in CO2, pCO2, pH
61
Respiratory acidosis is described as:
Increased CO2, pCO2; decreased pH
62
Serum Na: 136, K: 4 4, Cl: 92, bicarbonate: 40
Arterial pH: 7.32, pCO2: 79mm Hg
These results are most compatible with:
Respiratory acidosis
63
Quantitation of Na, K by ion-selective electrode is the standard method because:
Of advances in electrochemistry
64
What battery of tests most useful in evaluating an anion gap of 22mmol/L?
BUN, creatinine, salicylate, and methanol
65
Serum anion gap is increased in patients with:
Lactic acidosis
66
In respiratory acidosis, a compensatory mechanism is:
Plasma bicarbonate concentration
67
The solute that contributes the most to serum osmolality is:
Sodium
68
A sweat chloride of 55 mmol/L and a sweat sodium of 52 mmol/L obtained from a patient with a history of respiratory problems, the best interpretation is:
Borderline results, repeat test
69
Electrolytes for multiple myeloma patients should be run vis direct ISE and not indirect ISE because:
Sodium is falsely decreased due to protein boud calcium
70
What percentage of total serum calcium is nondiffusible protein bound?
40-50%
71
Fasting serum phosphate concentration is controlled primarily by:
Parathyroid glands
72
Calcium: increased in serum & urine
Alkaline phospate: decreased in serum, increased in urine
Alkaline phosphatase: normal or increased in serum
These results are most compatible with:
Primary hyperthyroidism
73
In strep pneumo pleural effusion, how would the protein value of the fluid would compare to serum protein
Decreased by half
74
First step of analyzing a 24 hour urine is to:
Measure total volume (preservation is pre-analytic)
75
Direction on which albumin migrates during electrophoresis at pH 8.6 is determined by
Ionization of carboxyl groups, yielding a net negative charge
76
Protein with the highest dye-binding capacity
Albumin
77
Relative migration of proteins on cellulose acetate is based on
Ionic charge
78
What amino acid has a sulfhydryl group?
Cysteine
79
In protein electrophoresis of a patient with biliary cirrhosis, which globulin fraction will be most elevated?
Gamma
80
What serum protein fraction is most likely to be elevated in patients with nephritic syndrome?
Alpha-2 globulin
81
A protein electrophoresis curve with a broad final peak and values as follows. What is this consistent with?
Total protein: 6.1 (n 6.0-8.8)
Albumin: 2.3 (n 3.6-5.2)
Alpha-1: 0.2 (n 0.1-0.4)
Alpha-2: 0.5 (n 0.4-1.0)
Beta: 1.2 (n 0.5-1.2)
Gamma: 1.9 (n 0.6-1.6)
Cirrhosis
82
A characteristic of bence Jones protein that is used to distinguish it from other urinary proteins is its solubility:
At 100C
83
At a pH of 8.6the gamma globulins move toward the cathode, despite being negatively charged. What is this phenomenon called?
Endosmosis
84
FFP will decline in which factors after 24 hours, converting it to Thawed Plasma?
Factor V, factor VIII (5, 8)
85
How many group A units would need to be screened to find one compatible with an Asub patient demonstrating anti-A1
5, 20% of the group A population is A1 neg
86
To confirm anti-P1, a neutralization study is performed. Both tubes (serum + neutralization, serum + saline) are negative. What conclusions can be drawn?
No confirmation possible from this result, saline control must be positive to be a valid test (negative indicates antibody too dilute to react)
87
Match serous fluids to their collection site
Pleural: thoracentesis
Pericardial: pericardiocentesis
Peritoneal: paracentesis
Ascites: paracentesis
88
If unable to test immediately, CSF glucose must be stored
Frozen
89
Polyuria is often associated with
Diabetes mellitus
90
Oligoclonal bands present on electrophoresis of concentrated CSF & on serum, what conclusions can be drawn?
Further testing required to r/o MS.
3 oligoclonal bands occurs in demyelinating diseases including, but not limited to MS
91
The identification of Bence Jones protein is best acomplished by:
immunofixation
92
Total iron binding capacity measures the serum iron transporting capacity of:
hemoglobin
93
The first step in the quantitation of serum iron is:
separation of iron from transferrin
94
an elevated serum iron with normal iron binding capacity is most likely associated with:
pernicious anemia
95
Decreased serum iron associated with increased TIBC is compatible with which disease state?
iron deficiency anemia
96
A patient with glomerulonephritis is most likely to present with:
BUN increased
97
Blood creatinine value of 5.0 mg/dL is most likely to be found with:
ammonia of 80 ug/dL
98
Technical problems encountered during the collection of an amniotic fluid specimen caused doubt as to whether the specimen was amniotic in origin. Which procedure/test would best establish that the fluid is amniotic?
creatinine measurement (differentiate from maternal urine)
99
What substance represents the end product of purine metabolism in humans?
uric acid
100
Oligoclonal bands are present on electrophoresis of concentrated CSF and also concurrently on tested serum of the same patient. Proper interpretation is:
nondiagnostic for MS, may be other demyelinating disease
101
Serum concentrations of B12 are elevated in:
chronic granulocytic leukemia
102
Absorption of B12 requires the presence of:
intrinsic factor
103
The procedure used to determine the presence of neural tube defects is:
alpha-fetoprotein
104
The hemoglobin that is resistant to alkali (KOH) denaturation is:
hgb F
105
In bilirubin determinations, the purpose of adding a concentrated caffeine solution or methyl alcohol is to:
allow indirect bilirubin to react with color reagent
106
In which disease state is conjugated bilirubin a major serum component?
biliary obstruction
107
A 21 yo M with nausea, vomiting, jaundice has the following results which can best be explained by:
total bili: 8.5 (n: 0-1.0)
direct/conj bili: 6.1 (n 0-0.5)
urine urobili: increased
fecal urobili: decreased
urine bili: pos
AST: 300 (n: 0-50)
ALP 170 (n: 0-150)
conjugated hyperbilirubinemia, probably due to hepatocellular obstruction
108
What are the following results most consistent with?
TP: 7.6 (n 6-8)
Alb: 4.1 (n: 3.5-5.0)
Ca: 9.6 (n: 8.5-10.5)
Phos: 3.3 (n 2.5-4.5)
Glu: 95 (n 65-110)
BUN: 16 (n 10-20)
UA: 6.0 (n 2.5-8.0)
Creat: 1.2 (n 0.7-1.4)
**T bil: 3.7 (n 0.2 - 0.9)**
**ALP: 275 (n 30-80)**
LDH: 185 (n 100-225)
**AST: 75 (n 10-40)**
Common bile duct stone
109
What substance gives feces its normal color
urobilin
110
Detection of carriers of hereditary coproporphyria should include analysis of:
fresh morning urine for delta-aminolevulinic acid
111
A fresh urine sample is received for analysis for "porphyrins" or "porphyria" without further information or specifications. Initial analysis should include:
porphyrin and porphobilinogen screen
112
Which of the heme biosynthesis enzymes are inhibited by lead?
porphobilinogen synthase
113
Serum haptoglobin
can be separated into distinct phenotypes by starch-gel electrophoresis
114
The most specific enzyme test for acute pancreatitis is:
lipase
115
The greatest activities of serum AST and ALT are seen in:
acute viral hepatitis
116
Malic dehydrogenase is added to the AST reaction to catalyze the conversion of:
oxalacetate to malate
117
Given the following results, what is the most likely etiology?
ALP: slight increase
AST: marked increase
ALT: marked increase
GGT: slight increase
acute hepatitis
118
a 10 year old admitted to pediatrics with an initial diagnosis of skeletal muscle disease. What would be the best confirmatory tests?
aldolase & creatinine kinase
119
In the immunoinhibition phase of the CKMB procedure what is inactivated?
The M subunit is inactivated, leaving the MB and BB functional via the B subunit
120
A serum sample drawn in ER from a 42yo M has the following results. What condition is consistent with these values?
CK: 185 (n 15-160)
AST: 123 (n 0-48)
CKMB: 6 (n 2-12)
Crush injury
121
What enzyme substrate is the most specific for prostatic acid phosphatase for quantitative endpoint reactions?
thymolphthalein monophosphate
122
What assay may be of help in establishing the presence of seminal fluid?
acid phosphatase, a major component of prostatic fluid
123
Lactate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase, and hydroxybutyrate dehydrogenase are all what type of enzyme?
catalyze redox reactions
124
The most consistent analytical error involved in the routine determination of HDL-cholesterol is caused by:
a small concentration of apoB containing lipoproteins after precipitation
Serum HDL is indirectly measured via 2-step process. 1) precipitation of non-HDL lipoproteins with polyanion-divalent cation reagent and centrifugation to obtain supernatant with only HDL. 2) measure cholesterol bound to HDL.
Challenge: precipitating reagent that takes apoB containing lipoproteins, Dextran sulfate w/ Mg has proven effective
125
What disease results from a familial absence of HDL?
Tangier disease
126
A 1yo F with hyperlipoproteinemia and lipase deficiency has the following lipid profile. What would a serum specimen from this patient refrigerated overnight look like?
Cholesterol: 300 mg/dL
LDL: Increased
HDL: decreased
Trig: 200mg/dL
Chylomicrons: present
creamy layer over clear serum
127
Chylomicrons are present in which dyslipidemia?
deficiency in lipoprotein lipase activity
128
The function of the major lipid components of the VLDL is to transport:
endogenous triglycerides
129
Assays for FT4 measure hormone not bound to: thyroxine-binding prealbumin, thyroxine-binding globulin, and ______
albumin
130
A 68yo F complains of being cold, recent weight gain without diet change. TSH is 8.7 (n=0.5-5.0). The patient most likely has:
primary hypothyroidism
131
A diabetic patient has urinary albumin excretion of 40mg/24h. Per NKF, urine albumin should be checked how frequently?
12 months
132
What is the formula for calculating absorbance given % transmittance of a solution?
2-log(%T)
133
Serum haptoglobin is:
Decreased in hemolytic anemia & other causes of in-vivo hemolysis
134
Definitive diagnosis of hereditary coporophyria is a marked increase of:
Fecal coproporphyrin III
135
Which blood gas electrode has a semi-permeable membrane, silver/silver chloride reference electrode, and a glass electrode?
pCO2
136
Urinary excretion product measured as an indicator of epinephrine production is:
Vanillymandelic acid (VMA), a major metabolite of epinephrine & norepinephrine
137
How many megakaryocytes should be seen in each 10x field of a bone marrow aspirate?
5-10
138
The most likely diagnosis for a patient with the following coag results is:
PT: 15.5 (N 10.5-12.5)
aPTT: 50.3 (N 24-34)
DDi: 1.62 (N <1.10)
FIBR: 35 (N 180-400)
FIBR AG: 268 (N 150-350)
Dysfibrinogenemia: immunologic fibrinogen assay will be normal, common pathway will be prolonged, Ddi elevated
139
What type of morphologically abnormal cells proliferate in AML with inv(16)?
Eosinophils
140
Several hours after birth an infant develops petichiae, purpuric hemorrhages, and plt count of 21. Most likely diagnosis is:
Autoimmune neonatal thrombocytopenia
141
vWF mediates platelet adhesion by binding to platelet receptor:
GPIb/GPIX/GPV
142
A patient with proximal venous thrombosis is on LMWH. After 3 days, what is the expected aPTT?
Normal, LMWH does not impact aPTT
143
Component associated *only* with rhe alternative complement pathway is:
Properdin factor B
144
Ambient temperature is 20C, how would this impact VDRL (venereal disease research laboratory) and RPR (rapid plasma reagin) tests?
Weaken reactions, leading to false negatives
145
A 54yo F previous smoker has hx of: fever, swollen joints, and morning stiffness. Testing reveals: elevated CRP, positive cyclic citrullinated peptide of 205 (cut-off 20), a speckled ANA pattern with titer of 1:320, and negative rheumatoid factor
Rheumatoid arthritis: has strongest correlation with smoking & cyclic citrullinated protein peptide antibodies. RA can occur w/o positive RF and may have positive ANA
146
Enzyme control tube in ASO hemolytic assay (antistreptolysin O) has no cell lysis. What is the most likely explanation?
Reduction of enzymes
147
Gamma hemolytic streptococci that blacken bike esculin agae but do not grow in 6.5% NaCl are most likely:
Group D streptococcus (Streptococcus bovis group)
148
A patient with severe sinusitis is admitted. A nasal culture reveals pure alpha hemolytic, depressed center colonies with distinctive mucoid appearance. Gram stain of the aspirate shows many PMN and GPC in pairs.
What tests would aid in organism ID?
Bile solubility, optochin sensitivity would help confirm Streptococcus pneumoniae.
149
When compared to direct specimen carbon fuschin stains used for detecting mycobacteria, fluorochrome stains are less sensitive for detecting mycobacteria classified as:
Rapid growers
150
A thoracic surgical wound specimen grows visible white colonies on BA at 48hr in CO2. Isolate is faintly staining GPR.
Most probable organism & more appropriate stain is:
Mycobacterium fortuitum & acid fast stain
M. fortuitum is a rapid growing Mycobacterium, which is associated with skin/subcutaneous tissue infections
151
The ability to make good decisions often depends on the use of a logic sequence of steps that include:
Defining the problem, obtaining facts, considering options
152
What parameter of a diagnostic test will vary with disease prevalence in a given population?
Accuracy
153
RhIG is not indicated in an Rh neg pregnancy if the patient has a:
Anti-D titer of 1:4096 (already actively immunized)
154
Antibody titers during pregnancy serve to:
Identify candidates for additional fetal monitoring
155
Key cytokines involved in the differentiation & proliferation of erythrocytes include:
Erythropoeitin (EPO) & granulocyte macrophage-colony stimulating factor (GM-CSF)
156
The glucose test pad on a test strip ma yield a false positive in the presence of:
Bleach
157
A mildly increased CSF lactate (25-30 mg/dL) is generally associated with:
Viral meningitis, other meningitis causes will be significantly elevated (>35mg/dL)
158
Presence of biliverdin may cause a urine sample to appear
Blue-green or yellow-green, due to photo-oxidation of bilirubin
159
Characteristics results of obstructive jaundice
ALP: +++
AST: +
ALT: +
GGT: +++
160
Regulation of calcium & phosphorus metabolism is accomplished by which gland?
Parathyroid
161
Tumor marker assays are most important for:
Monitoring the course of a known cancer
162
How do ticlopidine and clopidogrel inhibit platelets?
Blocking ADP mediated platelet aggregation
163
Which platelets antigen is the receptor for collagen?
GPIa/IIa complex
164
What parameter exhibits interfere due to clumped platelets in an electronic/laser particle cell counter
WBC
165
What test result is consistent with a diagnosis of PNH?
Diminished CD55 on hemapoetic cells
166
Hereditary deficiency of late complement components (C5, C6, C7, C8) can be associated with which condition?
Systems Neisseria infection due to reduced pathogen clearance
167
What are defining characteristics of Graves disease?
A firm goiter, presence of TRAb antibodies. It is predominantly seen in women & anti-TRAb is not solely diagnostic
168
GPC in chains are seen on gs from blood culture. Organism is beta hemolytic on BA. Further tests include:
PYR, bacitracin, hippurate to confirm Streptococcus pyogenes & S. agalactiae
169
Isolate from stool gives the following:
MAC: colorless colonies
HE: yellow-orange
TSI: a/a, no gas, H2S
Urea: positive
Yersinia enterolitica, colorless colonies common on MAC/HE but sucrose in HE can allow fermentation (yellow colonies).
Vibrio requires 1% NaCl, campy does not grow on MAC/HE, shigella is green on HE, salmonella is blue-green w/ black centers on HE
170
171
An antimicrobial susceptibility method to detect vancomycin intermediate Staphylococcus aureus is:
MIC broth dilution
172
What are the 3 steps of an individualized quality control plan?
Risk assessment, quality control plan, quality assessment
173
Kohler illumination is:
A method to ensure optimal contrast & resolution
174
What is the best choice for benchtop decontamination of HIV?
Sodium hypochlorite bleach (2 min wet time. HBV is 10 minutes)
175
An Rf value of 0.5 in thin layer chromatography means:
Solute moves half the distance of the solvent front. Rf is retention factor
176
In a group O individual with Le and SE genes, what ABH and LE antigens will be present in secretions?
Lea, Leb, H
177
What pair of immulnoglobulins are most efficient at activating thr classical complement pathway?
IgG1 & IgG3
178
If calcium oxalate crystals are observed in urine, what may this be an indication of?
Renal caliculi
179
The most specific method for glucose in all body fluids uses:
Hexokinase
180
An active metabolite of amitriptyline is
Nortriptyline
181
The drug procainamide is prescribed to treat cardiac arrhythmia. What biologically active liver metabolite is often measured simultaneously?
N-acetyl procainamide (NAPA)
182
A condition in which erythrocyte protoporphyrin is increased is:
Iron deficiency anemia
183
Valinomycin enhances selectivity of the electrode used to quantate:
Potassium
184
An automated method for measuring chloride which generates silver ions in tge reaction is:
Coulometry
185
Protein C and its contactor protein S proteolytically inactivate factors
Va and VIIIa
186
What are the characteristic features of iron metabolism in patients with anemia of chronic illness?
Serum iron: decreased
Transferrin saturation: decreased
TIBC: normal or decreased
187
Aspirin impairs platet function by:
Inactivating cyclooxygenase, blocking thromboxane A2
188
A type 1 AT deficiency will present with:
Decreased antigen & activity
(Type 2 will have normal antigen)
190
Which ion is bound to hemoglobin in methemoglobin?
Fe3
191
Which characteristic of Bernard-Soulier syndrome helps distinguish it from von Willebrand disease?
Giant platelets
192
What platelet response is expected in type IIb von Willebrand disease?
Increased aggregation to low-dose ristocetin
193
The ratio of kappa to lambda light chain producing cells in a normal individual is:
2:1
194
In primary biliary cirrhosis, what antibody is seen in high titers?
Anti-mitochondrial
195
Flocculation tests for syphilis use antigen composed of:
Cardiolipin & lecithin
196
Which thyroid antibodies cause hyperthyroidism by binding to the TSH receptor?
Anti-thyroid-stimulating hormone receptor (TRAb), causing constant stimulation
197
A fibrous skin nodule is removed from the back of a patient from Central America. A microfilaria seen upon microscopic exam is most likely:
Oncheroceroca volvulus, only microfilaria detected in skin snips
198
The biologically most active, naturally occurring androgen is:
testosterone
199
Beriberi is associated with what vitamin deficiency?
thiamine
200
Pellagra is associated with what vitamin deficiency?
D
201
The urinary excretion product measured as an indicator of epinephrine production is:
Vanillylmadelic acid (VMA)
202
Which hormone(s) regulate normal blood calcium levels?
parathyroid hormone
203
The most common form (95%) of congenital adrenal hyperplasia is 21-hydroxylase deficiency, which is detected by elevated plasma:
17-OH-progesterone
204
A diagnosis of primary adrenal insufficiency requires demonstration of:
Impaired response to ACTH stimulation
205
Clinical assays fro tumor markers are most important for:
monitoring the course of a known cancer
206
Increased concentrations of AFP in adults is most characteristically associated with:
hepatocellular carcinoma
207
The drug procainamide is prescribed to treat cardiac arrhythmia. What biologically active liver metabolite of procainamide is often measured simultaneously?
N-acetyl procainamide (NAPA)
208
Cocaine is metabolized to:
benzoylecgonie
209
Phenobarbital is a metabolite of:
primidone
210
Testing for the diagnosis of lead poisoning should include:
whole blood lead
211
Unless blood gas measurements are made immediately after sampling, in vitro glycolysis of the blood causes:
a fall in pH and a rise in pCO2
212
An arterial blood specimen submitted for blood gas analysis was obtained at 0830 but not received in the lab until 1100. The technologist should:
request a new specimen
213
What is the formula for determining pH based on CO2, pCO2?
pH = 6.1 + log[Salt/Acid]
-> pH = 6.1 + log[(CO2 - pCO2x0.03)/(pCO2 x 0.03)]
214
One IU of enzyme activity is the amount of enzyme that will, under specified reaction conditions of substrate concentration, pH, and temperature cause utilization of substrate at the rate of:
1umol/min
215
Based on the half-life of a substance, how does one calculate a steady-state level?
4 half lives to reach steady state
216
What is the Henserson-Hasselbalch equation?
pH = pKa + log (Salt/Acid)
217
The creatinine clearance mL/min is equal to:
[urinary clearance (mg/L) x vol (mL/hr)]/plasma creatinine (mg/L)
218
What are the formulas to calculate serum osmolality?
1.86[Na] + [Glu/18] + [BUN/2.8]
Some labs will add 9 to account for excess anions
219
What is the formula to calculate mEq/L from mg/dL?
[mg/dL]/[molar mass] x 10dL/L
if converting from BUN to Urea:
[mg/dL x (MW urea/MW 2N)] to account for changing from N measurement to whole molecule
220
In the atomic absorption method for calcium, lanthanum is used:
to prevent phosphate interference
221
Upon development of a thin-layer chromatogram for drug analysis, all drug spots (including standards) had migrated with the solvent. The most probable cause for this would be:
incorrect aqueous to nonaqueous solvent mixture
222
To detect barbituate abuse when analyzing urine specimens, immunoassay is the method of choice for screening. The method of choice for confirmation is:
gas chromatography/mass spectrometry
223
When separating serum proteins by cellulose acetate electrophoresis, using a buffer at pH 8.6, beta globulin migrates:
faster than gamma globulin
224
Hemoglobin S can be separated from Hemoglobin D by which method?
agar gel electrophoresis at pH 5.9
225
The buffer pH most effective at allowing amphoteric proteins to migrate toward the cathode (-) in an electrophoretic system is:
4.5
226
On electrophoresis, transient bisalbuminemia (or a grossly widened albumin zone) is associated with:
presence of therapeutic drugs in the serum sample
227
What serum proteins migrate with the beta globulins on cellulose acetate at pH 8.6?
C3 component of compliment
228
Blood pCO2 may be measured by
a self-contained potentiometric electrode
229
Which blood gas electrode is composed of Ag/AgCl reference electrode and glass?
pCO2
230
Most chemical methods for determining total protein utilize which reaction?
biuret
231
Bromcresol purple at pH 5.2 is used in a colorimetric method to measure:
ablumin
232
Magnesium carbonate is added in an iron binding capacity determination in order to:
remove excess unbound iron
233
What glucose measurement is glucose specific and colorimetric?
glucose oxidase
234
Before unconjugated bilirubin can react with Erlich diazo reagent, what must be added?
caffeine
235
In the Malloy and Evelyn method for the determination of bilirubin, the reagent that is reacted with bilirubin to form a purple azobilirubin is:
diazotized sufanilic acid
236
In the assay of LDH, what product is actually measured?
NADH
237
What glycolytic enzyme catalyzes the cleavage of fructose-1-6-diphosphate to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate?
aldolase
238
Assay of transketolase activity in blood is used to detect deficiency of:
thiamine
