LabCE Questions

pH alteration of normal blood in a closed vessel standing at 37 degrees C for 1 hour is approximately:

0.04 to 0.08 pH units.

The concentration of sodium chloride in an isotonic solution is?

0.85%

How would you correctly prepare 100 mL of 0.9% isotonic saline?

0.9 grams in 100 mL distilled water

What is the approximate percentage of individuals in the US who are heterozygous for HFE mutation?

10-12%. Hemochromatosis mutation.

A CSF glucose value is 62 mg/dL. What would you estimate the serum glucose?

93 mg/dL. CSF glucose is roughly estimated to be about 2/3 of the serum glucose level in mg/dL.

For the ANA test to be positive what must be present in the nucleus of the interphase cell?

A clearly discernible pattern

A kidney graft would have the best chance of survival post-transplantation if it were?

HLA Identical, mixed lymphocyte culture (-), ABO identical

What best describes high sensitivity CRP testing?

HS-CRP is a marker of chronic inflammation and is measured to predict the risk of cardiovascular disease.

The most frequent genotype among Rh neg people are:

rr

Serum TSH levels five-times the upper limit of normal in the presence of low T4 and low T3 uptake could mean what:

The thyroid has been established as the cause of hypothyroidism.

How long are healthy neutrophils expected to reside in the peripheral blood of an adult?

7-8 hours. Neutrophils reside in the peripheral circulation for only 7-8 hours before entering the tissues and body cavities via diapedesis.

A dilution commonly used for a routine sperm count is:

1:20

A pregnant female who was injected with RHG antenatally has a positive antibody screen at delivery. The antibody has been confirmed as anti-D and reacts only in the indirect anti globulin phase. Many laboratories consider reaction strength to be an indicator of whether the anti-D is likely passive or immune. To be considered probably passive, an anti-D reaction strength is typically less than or equal to which reaction grade?

2+

The proper storage requirements for granulocyte concentrates is:

20-24 degrees, <24 hours

The ketone component that is measured by the nitroprusside reaction is:

Acetoacetic acid.

Which adipokine is decreased in obesity, is anti-inflammatory, and increases insulin sensitivity?

Adiponectin. Its a protective cytokine synthesized and secreted almost exclusively by the adipocytes. Leptin is synthesized and released from adipose cells in response to adipose tissue changes. It reduces intracellular lipid levels in many types of body cells and thus improves insulin sensitivity, but is increased in obesity. Resisting is another inflammatory cytokine that is increased in obesity. Adipocyte-secreted TNF-a stimulates adipocytes to increase their release of non-esterified fatty acids and decrease adiponectin synthesis. It is increased in obesity.

Which serum protein shoes a decrease during an acute phase response?

Albumin. Albumin is a negative acute phase protein since it is found in decreased levels during acute phase responses. A1T, fibrinogen, and ceruloplasmin are all positive acute phase proteins that are found in increased levels during an acute phase response. Other positive proteins are alpha-1-acid glycoprotein, haptoglobin, C3, C4, C-reactive protein, and serum amyloid

Twelve weeks after onset of the disease, patients with uncomplicated acute hepatitis usually will demonstrate which protein in their serum?

Anti-HBe

Post-transfusion purport is characterized by:

Appearance of purport, platelet count less than 10,000/uL, and mucousal membrane bleeding

The colonies growing on the surface of a 5% sheep blood agar plate were recovered from a throat swab of a 19 year old girl with acute pharyngitis. The visual identification was S. pyogenes. Surprise! Gram stain revealed club-shaped gram positive bacilli with rudimentary branching. The most probable identification is:

Arcanobacterium hemolyticum. Must be considered in the differential identification of beta hemolytic bacteria recovered from throat swabs of young people with pharyngitis.

Micrococcus luteas

Bacitracin susceptible, resistant to furazolidone. GP coccus.

Which of the following organisms is not an aerobic organism: A) Francisella B) Bacteroides C) Pseudomonas D) Neisseria

Bacteroides

Which of the following are the beta thalassemia syndrome(s) whose genotype is B0/B+ A) Beta thalassemia silent carrier B) Beta thalassemia minor C) Beta thalassemia intermedia D) Beta thalassemia major

Beta thalassemia intermedia, beta thalassemia major. Double heterozygous, denotes there is one completely deleted beta chain gene and one partially deleted beta chain gene.

Which characteristic of CSF would be present if blood observed is due to a subarachnoid hemorrhage (SAH)?

Blood is evenly distributed in all tubes.

A beta-hemolytic gram positive coccus, isolated from the CSF of an infant, grew on sheep blood agar under aerobic conditions and was resistant to bacitracin disc. What test should be performed for the presumptive diagnosis of the organism?

CAMP test

Which cellular receptors are associated with normal B cells?

CD19, CD20, and Kappa or Lambda

Anticentromere antibodies

CREST syndrome

A manual white blood cell was performed by the hematology technologist. The cell counts for both sides were 99 and 164 respectively. All nine large squares were counted on each side. The dilution for this kit was pre-measured at 1:100. What should the technologist report as the white cell count ?

Can't report. The white cell counts from one side of the hemacytometer to the other are too discrepant to report.

The purpose of C3a and C5a, the split-products of the complement cascade is to:

Cause increased vascular permeability, contraction of smooth muscle, and release of histamine from basophils.

What barriers are recommended in microbiology laboratories where manipulation of biosafety level 3 agents is performed?

Class I or II biological safety cabinets, and self-closing double-door access.

Watch the tube effervesce, as I turn the milk into a mess

Clostridium perfringens

A students t-test is used for:

Comparison of two means from matched groups.

The renal threshold is best described as:

Concentration at which a substance in the blood spills into urine

Which hormone does not increase plasma glucose concentration by converting glycogen to glucose?

Cortisol.

Which statement about bacterial culture for C. diff is true? A) Routine bacteriological media will provide adequate recovery B) The culture is specific for toxigenic strains C) Culture on appropriate media provides an effective means of recovering the organism D) Culture for C. diff provides desirable turnaround times

Culture on appropriate media provides an effective means of recovering the organism. Blood agar and brucella agar are NOT adequate for recovering the organism.

What is the role of albuminuria testing?

Detect small urinary concentrations of albumin before there is irreplaceable renal damage.

Which condition is caused by deficient secretion of bilirubin into the bile canaliculi?

Dubin-Johnson Syndrome. Causes an increase of conjugated bilirubin without elevation of liver enzymes.

All the following will cause a falsely decreased erythrocyte sedimentation rate except: A) ESR tube is slanted B) EDTA tube is clotted C) EDTA tube is one-third full D) EDTA specimen is 24 hours old.

ESR tube is slanted will give a falsely increased ESR. Fibrin clots, diluted samples, and old samples give a falsely decreased ESR.

Patients with what condition would benefit most from washed red cells:

Elevated serum potassium. Washing not only reduces the number of leukocyte and platelets that are often responsible for febrile reactions, but also eliminates anticoagulants, ammonia, lactic acid, and potassium

An alpha-hemolytic, catalase negative, gram positive coccus from a wound culture gave these additional results: A disk: Neg Bile Esculin Hydrolysis: Pos CAMP: Neg Na Hippurate hydrolysis: Neg PYR: Pos What is the most probable identification?

Enterococcus species.

A pregnant female who received RhIg at 28 weeks gestation has a positive antibody screen at delivery. If the antibody has been confirmed as anti-D alone and reacts 1+ in the indirect anti globulin test with D+ red cells. Performing a titration to investigate if the anti-D is immune is good practice. T/F

False

The use of non-specific fluorescent dyes is the most specific method of measuring amplicons in real-time PCR. T/F

False

Maternal antibody titer is a good indicator of severity of HDFN. T/F

False. Maternal antibody titer is an unreliable indicator of severity of HDFN and is used to determine if clinical fetal monitoring is warranted.

Xanthochromia in CSF is characteristic of:

Hemorrhage. Xanthochromia is the pink, yellowish, or orange discoloration of the CSF mostly due to the presence of RBC degradation (hemolysis)

Which casts might be found in the urine of a healthy individual after strenuous exercise?

Hyaline casts and granular casts.

The laboratories completed the mixing study ordered for John Doe. The results are as followed: Initial APTT: 167 seconds Initial 1:1 mix with normal pooled plasma: 158 seconds Incubated 1:1 mix: 150 seconds. What is the most likely explanation for these results?

Immediate acting coagulation inhibitor. Most commonly lupus anticoagulant

What are indicators of sepsis?

Increased heart rate, leukocytosis, and increased body temperature

Which of the following is not a feature of SLE: A) Increased serum complement B) Positive ANA C) Circulating immune complexes D) Decreased serum complement

Increased serum complement. Complement is consumed during immune reactions involving SLE.

Elizabethkingia is the new genus name for the bacterium formerly called chryseobacterium meningosepticum, an important agent of neonatal meningitis. What biochemical characteristic is unique for the family flavobacteriaeceae among the non-fermenters?

Indole production.

Which two stages of cell division are the most important for reading ANAs?

Interphase and metaphase

Spectophotometric absorbance is related to % transmittance by:

Inversely and logarithmically. As the concentration of particles in a solution increases, the amount of absorbed light increases and the % transmittance decreases.

Primary sideroblastic anemia will be found in the following conditions except: A) Alcohol abuse B) Chloramphenicol therapy C) Iron deficiency anemia D) Thalassemia

Iron deficiency anemia.

What is not true of Real-Time RT-PCR?

It does not require the use of reverse transcriptase.

Donor red cells were collected July 12th of this year, the RBCs were then frozen in glycerol on July 17th. What should be the expiration date on the frozen RBC unit?

July 12th, 10 years from now

While ABO, Rh, Kell, Duffy, Kidd, and SsU are clinically significant, which antibodies generally react at only the Coombs phase (AHG)?

Kell, Duffy, Kidd

Predict the Lewis antigen phenotypic expression based on the following genotype (Le) (Se)

Le(a-b+) Le(a+b-) Le sese Le(a-b+) Le Se Le(a-b-) le Se/sese

How to differentiate between Listeria monocytogenes and Erysipelothrix rhusiophathiae:

Listeria is motile at RT, hydrolyzes esculin, and is catalase positive. Erysipelothrix is non-motile, does not hydrolyse esculin, and is catalase negative. Both ferment glucose.

What would happen as a result of hemodilution?

Low serum electrolyte values

A patient has the following test results, ANA positive, RA positive, complement decreased. These results are consistent with:

Lupus erythematosus. The ANA test tests for lupus, decrease in complement proteins indicates that the classic pathway may have been activated resulting in immune complexes, a clinically significant symptom of lupus.

Antigen processing is primarily accomplished by which cell type?

Macrophages.

Which assay, using 24-hour urine, is considered the best single screening test for pheochromocytoma?

Metanephrines.

The nitrite portion of the test strip can be used to:

Monitor antibiotic therapy, detect a bladder infection in an early stage in pregnant women, screen individuals with recurrent infections.

What situation suggests a traumatic tap may have occurred?

More blood is in tube 1 than tubes 2, 3, or 4.

What is the most likely identification of an acid-fast bacillus that demonstrates the following characteristics? Slow growth, cream to tan colored colonies when grown in the dark, and yellow pigment when exposed to light.

Mycobacterium Kansasii.

A 3 year old female was seen in a local ear, nose, and throat specialist for chronic ear pain. She had been treated several times for otitis media by her pediatrician with no resolution. Drainage from her ear grew an acid fast bacillus that gave the following biochemical reactions: Iron uptake: Positive Nitrate Reduction: Positive Arylsulfatase: Positive MAC: Growth after 5 days It should be identified as:

Mycobacterium fortuitum

The mycobacterium species most likely associated with the skin lesions representative of swimming pool granuloma is:

Mycobacterium marinum

Bence-Jones proteinuria can be seen in all of the following except: A) Amyloidosis B) Nephrotic syndrome C) Multiple myeloma D) Macroglobulinemia

Nephrotic syndrome. Bence-Jones proteins are monoclonal light chains excreted in the urine. Bence-Jones proteins have unusual heat solubility properties, in that they precipitate between 50-60 degrees C and redissolve at 90-100 degrees C.

A specimen from a 23-year-old female patient known to possess Bombay phenotype arrives in the blood bank. What kind of blood can be transfused to this patient? A) Type AB red blood cells B) Type O red blood cells C) Type O Neg blood D) None of the above

None of the above. Bombay individual will express type O in the front and back types.

Which describes the Westgard multi-rule R4S?

One date point is +2SD and a consecutive point is -2SD.

Which fungi is a common contaminant that grows rapidly, is at first white and then becomes bluish-green and very powdery with spore-bearing hyphae that characteristically form a brush?

Penicillium

Bence-Jones proteinuria will not be found in which diseases? A) macroglobulinemia B) Pernicious anemia C) Multiple Myeloma D) Amyloidosis

Pernicious anemia

Antimitochondrial antibodies

Primary biliary cirrhosis

Rh antibodies generally:

React best at 37 degrees Celsius

Anti-H:

Reacts more strongly with A2 cells than with group A1 cells. 0>A2>B>A2B>A1>A1B

What characteristic is common to all of these conditions: Hereditary spherocytosis, hereditary elliptocytosis, hereditary stomatocytosis, and paroxysmal nocturnal hemoglobinuria?

Red cell membrane defects

Which of the following antibodies is enhanced by enzyme treatment of red cells? A) MN, Duffy B) Rh, Lewis, Kidd C) Rh, A, B, S D) Duffy, A, B

Rh, Lewis, Kidd.

Antimyocardial antibodies

Rheumatic fever

Toxic granulation and vacuoles in a neutrophil most likely represent?

Septicemia

bDNA

Signal amplification using alkaline phosphatase and no thermal cycling

Adult Ascaris lumbricoides worms live in the:

Small intestine

Which organisms are frequently associated with infective endocarditis?

Staphlyococci, and streptococci

The most frequent cause of bacterial meningitis in older adults is:

Streptococcus pneumoniae

Which immune elements are involved in a positive TB test?

T cells and macrophages. T-lymphocytes with receptors for tuberculosis antigens will produce a positive skin test and secrete cytokines that will attract macrophages

NASBA

Target amplification using 3 enzymes and no thermal cycling

PCR

Target amplification using DNA polymerase and thermal cycling

TMA

Target amplification using reverse transcriptase, no thermal cycling

The measurement of 17-ketosteroids in urine is performed to assess primarily:

Testes and adrenal cortex

What applies to an assessment of the M:E ratio:

The erythroid tally/total used in calculating the M:E ratio is the sum of all nucleated red cell precursors, White blood cells used in the myeloid tally/total used to calculate the M:E ratio include neutrophilic precursors as well as eosinophil and basophil precursors, Lymphocytes and monocytes are not counted in the evaluation of the M:E ratio, and the M:E should always be interpreted in context with the overall bone marrow cellularity.

Which of the following statements is true for specific gravity measured by the reagent strip method? A) The reagent strip method is based on the relationship between ionic concentration and specific gravity B) The reagent strip method is based on the fact that light is refracted in proportion to the amount of total solids dissolved in the urine C) The reagent strip method is affected by the presence of x-Ray contrast in the urine specimen D) An alkaline pH would not affect the specific gravity result using a reagent strip method

The reagent strip method is based on the relationship between the ionic concentration and specific gravity. Urine SQ increases as ionic concentration increases. Reagent strip method is NOT affected by X-Ray contrast media, but the refractometry method is. An alkaline pH would decrease the SG, not increase it.

The part of the molecule responsible for differences among immunoglobulin classes is:

The heavy chains.

Why do so few patients transfused with un-crossmatched red cells in an emergency experience a hemolytic transfusion reaction?

The incidence of unexpected red cell antibodies is relatively low.

The antibody most frequently present in SLE is directed against?

The nuclear antigen

What serological test results may occur in a patient experiencing a hemolytic transfusion reaction due to antibodies such as anti-c and anti-K?

The patients antibody strength may initially decrease, patient may develop a positive DAT with mixed-field agglutination, the patients antibody becomes undetectable, and the patients antibody increases in titer weeks later.

What nitrogenous base is present in DNA, but not in RNA?

Thymine

The relative centrifugal force of a centrifuge may not be affected by what?

Time

An acute hemolytic reaction may be caused by what:

Transfusion of ABO incompatible blood, and exposure to a red cell antigen when the corresponding antibody is present.

Which of the following specimen processing examples is NOT considered a processing error that can have a negative impact on the test results: A) Transporting an ammonia specimen to the laboratory in an ice slurry B) Centrifuging a plasma sample 4 hours after collection C) Rimming the clot in a serum collection tube prior to centrifugation D) A blood specimen that is frozen and thawed a few times before testing

Transporting an ammonia specimen to the laboratory in an ice slurry.

Antineutrophilic antibodies

Wegeners granulomatosis

The gene loci for the alpha globin chains are adjacent to the locus for which other globin chain?

Zeta.

A normal hemoglobin molecule is comprised of:

four heme and hour globin chains.