LabCE practice

What are the four nitrogenous bases that are found in RNA?

Adenine, guanine, cytosine, and uracil

All of the following are Lancefield carbohydrate antigens found on beta hemolytic Streptococcus species. All of the following antigens are found on organisms from the Streptococcus anginosus group EXCEPT?

B

It has already been established that the gated cell population is lymphocytic in nature. CD19 and CD20 cell surface antigens both appear on what type of lymphocytes?

B cells

All of the following media types should be inoculated for cerebrospinal fluid (CSF), EXCEPT:

Brucella agar plate (BRU)

Which of the following best describes the benefits of the RPR or VDRL tests:

Monitoring course of treatment

Which of the following statements is true regarding hyposegmented neutrophils?

Nucleus may be round, peanut-shaped or bilobed.

Which of the following phrases best describes a segmented neutrophil?

Cytoplasm appears pink-purple due to small specific granules.

Which substance acts as a mordant in the Gram stain process?

Gram's iodine

Which of the following antigen groups is closely related to the ABO antigens on the red cell membrane?

I, i

Which of the following analytes would be decreased due to delay in centrifugation?

Ionized Calcium

Which of the following is the first step in the four steps of Koch's postulates?

Observe the same organism in all cases of a given disease

Select the primary reagent components used in the Jaffe reaction for creatinine.

Saturated picric acid and sodium hydroxide

Aspirin ingestion prevents the synthesis of this signaling molecule in the platelet?

Thromboxane A2

Which of the following corresponds to a way to prevent infection with Sporothrix schenckii?

Wear gloves when gardening

Which of the following analytes would be increased due to delay in centrifugation?

creatinine

Ionized calcium is currently most commonly measured using which of the following method?

Calcium ion selective electrodes

Suppose a patient with stiffness in her fingers has a positive antinuclear antibody (ANA) test with a centromere pattern at a 1:1280 titer. What is the most likely diagnosis?

CREST syndrome

Which of the following conditions may produce the findings indicated by the arrows in the image on the right?

May-Hegglin anomaly

Which of the following medications is considered an antineoplastic drug?

Methotrexate

When preparing platelet concentrates from whole blood, after the second spin and excess plasma has been expressed from the platelets, what is the next step in platelet preparation?

Allow the platelets to rest for 1-2 hours at 20-24°C.

Which of the following is the first stage in the life cycle of a hemoflagellate?

Amastigote

Which of the following autoantibodies are found in a patient with Hashimotos thyroiditis?

Antithyroid peroxidase (TPO)

Codocytes (target cells) are an expected finding in all of the following phenotypes of beta thalassemia, EXCEPT?

Beta thalassemia minima

Which of the following choices best describes the primary function of antibodies?

Binds with antigen

Which of the following statement is INCORRECT regarding the bone marrow biopsy specimen?

Cellular morphologic detail can be determined.

This serum protein electrophoresis scan most likely represents which condition?

Chronic inflammation There is a broad based increase in the gamma band

Which of the following clinical laboratory departments performs the most tests?

Clinical Chemistry

The renal threshold is best described as:

Concentration at which a substance in the blood spills into urine

A Rh negative individual has produced an anti-D antibody. Which situation has the ability to stimulate this production of anti-D?

Delivering a Rh positive baby.

Illustrated in this photograph is a close-in view of colonies growing on the surface of xylose lysine deoxycholate (XLD) agar. The bacterial species most likely producing the colonies shown here is:

Edwardsiella tarda

Which of the following processes does NOT occur during primary hemostasis?

Fibrin strands added to the newly formed clot.

What would be the best way to determine how much RhIg should be given to a postpartum female who received RhIG antenatally and demonstrates the anti-D antibody at delivery?

Flow cytometry

Which of these methods measures fetal hemoglobin or D positive red cells or both to evaluate fetomaternal hemorrhage?

Flow cytometry

Platelets are:

Fragments of megakaryocyte cytoplasm and do not contain nuclei

Which genetic description will NOT contain Bart's hemoglobin at birth ?

Heterozygous alpha thalassemia-2

Which of the following would be considered the definitive host of a parasite?

Host in which parasites reproduce sexually

Using molecular methods to identify organisms can provide GREATER specificity when compared to phenotypic methods. Which of the following organisms would molecular methods not be beneficial over phenotypic methods in identification?

Klebsiella species

Which of the following tests on amniotic fluid would be included when assessing fetal lung maturity:

L/S ratio

The presence of an increased number of hypersegmented neutrophils in the peripheral blood, as shown in this image, is an indication of which of the following conditions?

Megaloblastic anemia

Each of the cells below can be found in all types of body fluids EXCEPT:

Mesothelial cells

What is the characteristic RBC that is uniquely associated with HbSS?

Sickle cell (drepanocyte)

All of the following should be done when centrifuging specimens, EXCEPT?

Specimens with anticoagulant should sit for 20 minutes before centrifugation.

The bacterium in the image to the right is also referred to in the quote below, what is the identification of this bacteria?

Streptococcus pyogenes

An organism isolated from a sputum specimen and appeared as a dry, wrinkled, off-white colony on sheep blood agar. A Gram stain was performed and Gram positive branching rods were seen. In addition, a modified acid fast was performed and was positive. The organism was later identified as a Norcardia species. Which of the following antibiotics is the appropriate treatment?

Sulfonamides

A mother's serologic results are shown above. Her newborn types as group A Rh positive with a (1+) positive direct antiglobulin test (DAT). Which of the following investigative tests would be most useful to resolve the cause of the positive DAT and should be done FIRST?

Test newborn's plasma against group A1 red cells and group O antibody screen cells by IAT.

The qualitative differences between A1 and A2 phenotypes includes all of the following EXCEPT:

The lack of agglutination of patient red cells with anti-A reagent.

Which of the following is used to analyze risk and highlight aspects of a process that should be targeted for improvement?

failure mode and effects analysis (FMEA)

Identify the nucleated blood cell:

Monocyte

If detected in antibody screen testing, which of the following antibodies is NOT considered clinically significant in prenatal patients?

Anti-Leb

Which of the following viral families contains DNA as its nucleic acid?

Poxviridae

After an acute myocardial infarction (AMI), myoglobin levels will rise within 3 hours and peak at 8-12 hours. When will they return to normal?

18-30 hrs

Once the seal on a unit of packed red blood cells is opened, how long can the unit be stored in the refrigerator prior to administration?

24 hrs

The normal Myeloid-to-erythroid ratio (M:E ratio) ranges from:

2:1 to 4:1

What is the minimum amount of time a specimen without additive or anticoagulant should be allowed to clot before centrifugation?

30 min

Calculate the mean corpuscular hemoglobin content (MCHC) when Hgb = 15 g/dL (150 g/L), RBC count = 4.50 x 106/µL (4.50 x 1012/L), and Hct = 47% (0.47).

31.9 g/dL

What is the maximum number of white blood cells allowed in a leukocyte-reduced unit of red blood cells?

5 x 10^6

Approximately how many doses are required to obtain a steady-state oscillation allowing for peak and trough levels to be evaluated?

5-7

What is the molarity of an unknown HCl solution that has a specific gravity of 1.10 and an assay percentage of 18.5%? (Atomic weight: HCl = 36.5)

5.6 mol/L

Given the following information, calculate the results in mg/24 hrs for a 24 hour urine protein. Total volume for 24 hours = 2400 mL Urine protein = 2.7 mg/dL

64.8 mg/24hrs

A 1:100 dilution of a patient's peripheral blood was made and a total of 136 platelets were counted in 5 squares of the RBC area of a Neubauer-ruled hemocytometer. What is the Platelet count? Note: The volume correction factor is 50 µL.

680 x 10^3/uL

From the IgG molecule illustration, which region is the heavy chain?

A

A hepatic function panel A consists of which of the following tests?

AST, ALT, Alkaline Phosphatase, Total Protein, Albumin, Total Bilirubin, Direct Bilirubin

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

Acetoacetic acid

Which of the following blood tests is used in the determination of prostate cancer?

Acid phosphatase

Which Gram positive bacilli will show a positive result for urease?

Actinomyces naeslundii

Ion selective electrodes, for pH determinations, are called selective rather than specific because they actually measure the:

Activity of one ion much more than other ions present

The colonies illustrated in the upper photograph were recovered from the aspiration of nasal secretion from a patient with acute sinusitis. The 48 hour colonies on blood agar are relatively small, entire, white, and non-hemolytic. Colonies growing on chocolate agar are also small, smooth and entire with a light yellow pigmentation. On Gram stain, pale-staining, Gram negative coccobacilli are observed, with a tendency to form long, narrow filaments. The lower photograph reveals tube reactions with a KIA: Acid/Acid and the oxidative utilization of several carbohydrates except xylose and mannose. Nitrate reduction is positive and ornithine and arginine decarboxylases are negative. From the observations, select from the multiple choices the genus/species name of this isolate.

Aggregatibacter aphrophilus

All of the following are factors that will affect migration in gel electrophoresis, EXCEPT?

Amount of light present

All of the following laboratory tests are used to determine kidney function, EXCEPT?

Amylase

8-Hydroxyquinoline and Ortho-Cresolphthalein complexone (CPC) reagent is commonly used in the determination of:

Calcium

The measurement of sodium and chloride in sweat is the most useful test for the diagnosis of what condition/disease?

Cystic fibrosis

All of the following represent a 2 week temporary deferral from donating blood or blood products EXCEPT:

German measles (rubella) vaccine

The iron containing pigment found in red blood cells whose function is to bind oxygen and carbon dioxide is called:

Hemoglobin

Donor red blood cells (RBCs) were collected on July 12th of this year. The RBCs were then frozen in glycerol on July 17th (5 days later) and stored at -65o C.

July 12th; 10 years from collection date

A variety of additives are used in blood collection tubes. Which of the following additives prevents clotting by inhibiting thrombin and thromboplastin?

Lithium or sodium heparin

All of the following are causes of hypernatremia EXCEPT:

Low aldosterone production

Which of the following is the most likely identification of an acid fast bacilli recovered from an induced sputum with these culture findings? Slow growth at 37o C Niacin test = negative Pigmented photochromogenic Nitrate test = positive Catalase = positive

Mycobacterium kansasii

In immunohematology, an antithetical relationship exists between M antigen and which of these antigens?

N antigen

What type of lymphocyte appears as a large cell with abundant cytoplasm and a few azurophilic granules?

Natural killer lymphocyte

Which three hormones are known to regulate serum Ca2+ by changing their secretion rate in response to changes in ionized Ca2+?

PTH, vitamin D & calcitonin

What procedure utilizes leukapheresis to collect the buffy coat from whole blood?

Photopheresis

When a patient has a bile duct obstruction, the bilirubin test portion of the reagent strip is:

Positive because conjugated bilirubin is present and is excreted by the kidneys.

Which of the following conditions would be suggested by a jaundiced patient experiencing a marked rise in alkaline phosphatase (ALP), conjugated bilirubin, and a slight rise in alanine aminotransferase (ALT)?

Post-hepatic cholestasis

Which of the following tests require a 72 hour stool (fecal) collection?

Quantitative fecal fat

The 12 µm in diameter cyst illustrated in the lactophenol-stained mount observed in the photomicrograph can be identified as Entamoeba histolytica. Based on the characteristics seen in the image, what feature of the chromatoid bar prompts this differential identification?

Rounded ends

Which of these cells tend to occur in tight clusters and may have prominent nucleoli, immature chromatin, and scant cytoplasm?

Tumor cells

The type of hypersensitivity reaction associated with macrophage activation, cytokine-mediated inflammation is:

Type IV Cell mediated hypersensitivity (T-cell dependent)

Which two of the following crystalline elements are found in acid urine:

Tyrosine and cystine

Acetest® can be used to test for ketones in:

Urine, serum, and whole blood

The most significant class of microbial targets for Natural Killer (NK) cells is:

Viruses

Which of the following casts is characteristically associated with acute pyelonephritis?

White cell

At many hospitals, patients with sickle cell disease are given phenotypically matched units of blood. This policy is often used to help prevent alloimmunization to common RBC antigens in patients who are regularly transfused. A patient who regularly comes to your hospital demonstrates the following phenotype on her RBCs: C antigen positive; E antigen negative; K antigen positive. The patient's doctor requests a single unit of crossmatched packed RBCs. Based on the antigen prevalence indicated below, how many units of ABO compatible packed RBCs will you phenotype to find one to transfuse to this patient? Antigen frequencies C antigen positive: 68% E antigen positive: 22% K antigen positive: 9%

1 unit STEP 1: Since 22% of donors are positive for E antigen, 78% are negative for E antigen. 78% expressed as a decimal is 0.78 STEP 2: The reciprocal of 0.78 is calculated as follows (1/0.78) = 1.3

Rule out on blood bank panel

not clinically significant (anti-Lua, -Lea).

A culture was taken of a conjunctival exudate. The bacterial species, represented by the tiny colonies seen on this chocolate agar plate were recovered after 48 hours incubation at 35°C. The isolate was cytochrome oxidase positive and highly susceptible to penicillin. What is the most likely identification of this organism?

Moraxella lacunata