Subject Review Presentation

Which organism may be recovered from the eye of a patient suffering from keratitis? - Entamoeba histolytica - Paragonimus spp. - Trichinella spp. - Acanthamoeba spp.

- Acanthamoeba spp. Acanthamoeba spp., Toxoplasma gondii, Loa Loa, and Microsporidia are the most likely parasites recovered from the eye and be the cause of keratitis. Both Giemsa and calcofluor white stains should be used on the specimen to identify cysts and trophozoites. Entamoeba histolytica is one of the most likely parasites recovered from the liver and spleen. Paragonimus spp. is one of the most likely parasites recovered from the lung. Trichinella spp. is one of the most likely parasites recovered from the muscle.

The most common cause of acute meningitis associated with CSF shunts is: - Coagulase-negative staphylococci - Naegleria fowleri - Citrobacter koseri - Streptococcus pneumoniae

- Coagulase-negative staphylococci Coagulase-negative staphylococci cause approximately 50% of acute meningitis cases associated with CSF shunt infections. Other skin flora such as species of Corynebacterium and Cutibacterium (Propionibacterium) acnes also are leading causes of CSF shunt infections. Naegleria fowleri causes primary amoebic meningoencephalitis, Citrobacter koseri is a cause of neonatal meningoencephalitis, and Streptococcus pneumoniae remains an important cause of meningitis in adults.

Disorders affecting the thyroid, pituitary, and adrenal glands can all lead to anemia (mild to moderate). This is most often associated to which of the following? - Increase in direct effector hormones - Increase in tropic hormones - Decrease in erythropoietin (EPO) - Decrease in tropic hormones

- Decrease in erythropoietin (EPO) Disorders of the endocrine system, including the thyroid, parathyroid, pituitary, and adrenal glands, can result in a mild to moderate anemia due to a decrease in EPO.Direct effector hormones act directly on peripheral tissue. An increase in a direct effector hormone would not result in anemia.Tropic hormones are those that act on another endocrine gland. An increase or a decrease in tropic hormones would not result in anemia.

The amoeba that lives in the gumline of the mouth is known as: - Entamoeba polecki - Trichomonas tenax - Entamoeba gingivalis - Acanthamoeba species

- Entamoeba gingivalis Entamoeba gingivalis is the correct answer because the species name "gingivalis," which is related to the term gingivitis, aids in determining that this organism is a mouth-dweller. All of the organisms that begin with the word Entamoeba are classified as amoebae.

Which of the following factors is Vitamin K-dependent? The correct answer is highlighted below - Factor I - Factor VIII - Factor IX - Factor XI

- Factor IXVitamin K is required for the hepatic synthesis of factors II, VII, IX, and X. A deficiency of these factors will result in a prolongation of the PT. Vitamin K is also required for the synthesis of protein C, protein S, and protein Z. Factors I, VIII, and XI are not vitamin K-dependent.

A deficiency in which of the following coagulation factors will produce an abnormal prothrombin time (PT) test result but will not affect the activated partial thromboplastin time (APTT) test result? - Factor X - Factor VII - Factor V - Factor II

- Factor VII Factor VII is only involved in the extrinsic pathway, so a deficiency will not be detected by the APTT test. Factors X, V, and II are all factors in the common pathway. Deficiencies in any of these will affect both the APTT and the PT test results.

In hemoglobin synthesis, which enzyme is responsible for adding iron in the last step? - ALA Synthase - Ferrochelatase - PBG Synthase - Protoporphyrinogen oxidase

- Ferrochelatase ALA synthase is the enzyme used in the first step to create delta-aminolevulinic acid (ALA); PBG synthase is used in the second step to condense two ALA molecules into porphobilinogen; protoporphyrinogen oxidase catalyzes the second to last step to create protoporphyrin.

What is the primary target of HIV? - Heart - Neutrophils - B-cell lymphocytes - Helper T-cell lymphocytes

- Helper T-cell lymphocytes (CD4) HIV infects helper-T cell lymphocytes. Lymphocytes are essential to the adaptive immune response. Another cells that is a target of HIV is a macrophage. Heart is incorrect because immune cells are the primary cells that are infected. Hence, the name Human Immunodeficiency Virus (HIV). Neutrophils is incorrect even though they are a type of white blood cell that plays a role in our immune response; however, they are not infected by HIV. Neutrophils primarily fight against bacterial infections.B-cell lymphocytes is incorrect even though they are lymphocytes. However, they are not susceptible to infection by HIV.

A quick mathematical check which can be applied to verify that the hemoglobin and hematocrit values on a complete blood count correspond with each other would be: - Hematocrit X 3 = hemoglobin - Hemoglobin X 3 = hematocrit - Hemoglobin / hematocrit = 3 - Hemoglobin + hematocrit = 3

- Hemoglobin X 3 = hematocrit The rule of three is often used by laboratory professionals to check the accuracy of the RBC count, hematocrit, and hemoglobin values obtained. Based on the rule of three, RBC count X 3 = hemoglobin X 3 = hematocrit

The life span of RBCs containing Hemoglobin H is typically: - Less than 120 days - 100-120 days - 120-140 days - Greater than 140 days

- Less than 120 days The normal lifespan of RBCs is 120 days. The life span of an RBC containing Hemoglobin H inclusions is significantly decreased because the RBC membrane is compromised when macrophages attempt to remove this unstable hemoglobin, which is precipitated just inside the membrane. This results in a moderate hemolytic anemia with decreased RBC survival.

GGT (gamma-glutamyltransferase) is an enzyme found in many body tissues including the kidney, prostate, brain, pancreas, and liver, however, its clinical applications is confined to the evaluation of what system? - Pancreas - Liver - Kidney - Brain

- Liver GGT is used to assess disorders of the liver and biliary system. While found in other tissues (Brain, Kidney, Pancreas), the clinical significance is solely in the liver and biliary systems due to the higher amounts and specificity in the liver.

All of the following would be considered a normal part of a routine electrolyte panel (profile), EXCEPT? - Sodium - Potassium - Magnesium - Chloride

- Magnesium Magnesium is the 4th most abundant cation in the body but is not included in the electrolyte panel testing. The electrolyte panel consists of potassium (K+), sodium (Na+), chloride (Cl-), carbon dioxide (in form of bicarbonate HCO3-).

A cause of FALSE-POSITIVE result in the rapid plasma reagin (RPR) test for syphilis is: - Gastroenteritis - Gonococcal urethritis - Malaria - Streptococcal pharyngitis

- Malaria The RPR test can show false positive results in the absence of syphilis if infectious mononucleosis, SLE, antiphospholipid antibody syndrome, hepatitis A, leprosy, or malaria are present. The RPR test results may also be positive due to other treponemal diseases such as pinta and yaws. Gastroenteritis, gonococcal urethritis, or streptoccocal pharyngitis do not produce false-positive RPR reactions.

What is the term used to describe inadequate blood supply that decreases availability of oxygen to the myocardium? - Acute myocardial infarction (AMI) - Angina - Congestive heart failure (CHF) - Myocardial ischemia

- Myocardial ischemia Myocardial ischemia - an inadequate blood supply that decreases the availability of oxygen. CHF - a clinical syndrome caused by heart disease, represented by abnormal sodium and water retention and breathlessness, usually resulting in edema. AMI - cardiac tissue death (necrosis) due to lack of oxygen caused by obstruction of circulation. Angina - chest pain caused by an inadequate supply of oxygen to heart myocardium.

The episodes of fever and chills experienced by patients suffering from malaria are known as: - Parasitemias - Inflammations - Paroxysms - Relapses

- Paroxysms The increments in which paroxysms occur in patients suffering from malaria vary by species: Plasmodium vivax, 48 hours; Plasmodium ovale, 48 hours; Plasmodium malariae, 72 hours; and Plasmodium falciparum, 36 to 48 hours. The best time to collect peripheral blood for the examination of these organisms (as the greatest number of them may be present) is in between the paroxysms.

Which of the following organisms appear Gram-positive when using the Gram Stain? - Haemophilus influenzae - Escherichia coli - Peptostreptococcus anaerobius - Bacteroides fragilis

- Peptostreptococcus anaerobius Peptostreptococcus anaerobius is an anaerobic Gram-positive coccus that is typically observed in chains. A definitive identification can be made if the organism exhibits a zone of inhibition around the SPS disk under anaerobic conditions. This organism isn't a frequent pathogen but has been implicated in brain abscesses, meningitis, aspiration pneumonia, and lung abscesses. Haemophilus influenzae, Escherichia coli, and Bacteroides fragilis are all Gram-negative organisms. H. influenzae is a small Gram-negative coccobacillus, while E.coli and B.fragilis are both Gram-negative rods.

Which of the following is a common clinical symptom that is directly related to thrombocytopenia? - Shortness of breath - Joint pain - Petechiae - Fever

- Petechiae If the platelet count reduces to less than 30 x 109/L, petechiae may be observed. Petechiae are small pinpoint hemorrhages that indicate bleeding from subcutaneous blood vessels into intact skin. The remaining symptoms would not be directly related to thrombocytopenia. Shortness of breath and joint pain may occur with coagulation factor abnormalities where the bleeding is internal into deeper tissues and joints.

Which of the following is an example of a macroscopic urinalysis abnormality? - Glitter cells - Positive protein - Waxy casts - Red blood cell casts

- Positive protein The macroscopic abnormalities are detected by the physical and chemical portions of the urinalysis. Obtaining a positive protein during the chemical portion of a urinalysis would be an example of a macroscopic abnormality. The presence of glitter cells, waxy casts, and red blood cell casts could only be determined by the microscopic examination of the urine sample.

A patient has a hypercellular bone marrow and is suspected of having a myeloproliferative disorder. Laboratory features include: excess megakaryocyte proliferation and atypia, marked marrow fibrosis, and the JAK2 mutation. The most likely diagnosis is: - Primary Myelofibrosis (PMF) - Chronic Myelogenous Leukemia (CML) - Chronic Neutrophilic Leukemia (CNL) - Essential Thrombocythemia (ET)

- Primary Myelofibrosis (PMF) The megakaryocyte proliferation and marrow fibrosis are most characteristic. CML does not have the JAK 2 mutation and has excess proliferation in many of the myelocytic lines. CNL is characterized by neutrophilia and the CSFR mutation. ET has excess megakaryocyte proliferation and the JAK2 mutation, but platelet counts are higher. Also, though there can be some fibrosis, it is not as characteristic or excessive as in PMF.

Washing red cells may be performed to remove what from the unit? - White blood cells - Platelets - Plasma - Proteins

- Proteins Washing red cells may remove some white blood cells, but it is not an efficient way to do so. Irradiation of the unit is the best approach when removing white blood cells. During collection the whole blood unit undergoes a light spin to separate the red blood cells from the plasma and platelets. The platelet-rich plasma is diverted into another unit for further processing. Though there is some residual plasma in the red cell unit, it is not enough to cause a reaction.

The slide coagulase test is a rapid method for identifying which of the following organisms? - Staphylococcus hominis - Streptococcus pneumoniae - Staphylococcus aureus - Neisseria gonorrhoeae

- Staphylococcus aureus The coagulase slide test is used to differentiate S. aureus from coagulase-negative staphylococci. Since not all isolates of S. aureus are detected by the slide coagulase test, suspicious organisms negative by the slide test must be confirmed by the tube coagulase test.

Which of the following procedures should be followed when storing supplies or reagents that do not have a manufacturer-assigned expiration date? - It doesn't matter how they are stored because there is no assigned expiration date. - Mark each container of supply or reagent with the date of receipt before putting it into the storage area. - Store supplies in a manner that ensures the oldest will be used first. - Store supplies in a manner that ensures the newest will be used first.

- Store supplies in a manner that ensures the oldest will be used first. This ensures the oldest is used first. It would then logically follow that newer supplies/reagents are stored behind older supplies/reagents.

A vaginal swab for anaerobic culture is received in the laboratory. How should this specimen be handled? - The specimen should be processed for culture - The specimen should be rejected - The order should be changed to an aerobic culture - The specimen should be discarded

- The specimen should be rejected This vaginal specimen for anaerobic culture should be rejected. Anaerobic organisms are present as normal flora in the vagina, and thus culturing for these organisms does not necessarily indicate an infection and can provide an inappropriate clinical picture to the physician.

Which of the following is a characteristic of Francisella tularensis? - Tiny, weak-staining, gram-negative coccobacilli - Oxidase and urease positive - Subcultures grow easily and quickly on sheep blood agar (SBA) - Tiny, gram-positive rods

- Tiny, weak-staining, gram-negative coccobacilli. In gram stains, F. tularensis is a tiny, weak-staining, gram-negative coccobacilli. The organism is oxidase and urease negative, slow growing, and fastidious. It will grow initially on sheep's blood agar (SBA), but growth is poor or absent on subculture. It is difficult to see individual colonies on SBA in growth that is less than 24 hours old. F. tularensis prefers cystein-enriched media such as chocolate (CHOC), Thayer-Martin (TM), buffered charcoal-yeast extract (BCYE), and thioglycollate (THIO).

The process of pipetting 1.0 mL of plasma or serum into a tube containing 1.0 mL of saline, mixing the contents, and then repeating the same procedure into several additional tubes also containing 1.0 mL of saline is referred to as: - One to one serial dilution - Two-fold serial dilution - Multiple dilution - Decreasing serial dilution

- Two-fold serial dilution Two-fold serial dilutions result in "halving" the amount of serum with each successive dilution. Basically, reducing the concentration of the serum in half with each dilution.

An obese adult with premature arteriosclerosis is seen in the clinic. When her serum is tested no chylomicrons are present, LDL levels are normal, and VLDL levels are increased. There is an increase in triglycerides and a slight increase in cholesterol. Lipoprotein electrophoresis reveals a heavy pre-beta band. She has no skin rash and uric acid is increased. This patient most likely has what type of hyperlipoproteinemia? - Type I - Type III - Type IV - Type V

- Type IV Type I is associated with deficiencies of lipoprotein lipase. Type II is the most common form; classified into type IIa and type IIb, depending on whether there is an elevation in the triglyceride level in addition to LDL cholesterol. Type III is associated with high chylomicrons and IDL. Type V is similar to type I, but with high VLDL in addition to chylomicrons.

Each of the following practices will better ensure the successful recovery of Campylobacter jejuni from stool specimens except: - Incubation at 42°C - Use of Campy BAP medium - Use of selenite enrichment broth - Incubation in an atmosphere of 5% O2, 10% CO2, and 85% N2

- Use of selenite enrichment broth Campylobacter jejuni grows optimally at 42°C, higher than the typical incubation temperature of 35-37°C. Campylobacter jejuni also requires a selective medium due to the high amount of normal flora in stool. Common mediums for Campylobacter are Campy BAP, Skirrow's, Butzler, and charcoal cefoperazone deoxycholate agar (CCDA). Finally, Campylobacter requires a microaerophilic environment during incubation, which contains 5% O2, 10% CO2, and 85% N2. Selenite enrichment broth is a broth that enhances the recovery of Salmonella and some strains of Shigella from stool specimens.

The deficiency in which fat-soluble vitamin is associated with night blindness? - Vitamin A - Vitamin E - Vitamin D - Vitamin K

- Vitamin A Vitamins A, E, D, and K are fat-soluble. Vitamin A deficiency - night blindness, growth retardation, abnormal taste response, dermatitis, and recurrent infections. Vitamin E deficiency - mild hemolytic anemia (newborn), red blood cell fragility, and ataxia Vitamin D deficiency - rickets (young) and osteomalacia (adult). Vitamin K deficiency - hemorrhage (ranging from easy bruising to massive bruising) and post-traumatic bleeding.

A urine production of less than 400 mL/day is: - Consistent with normal renal function and water balance - Termed isosthenuria - Defined as oliguria - Associated with diabetes mellitus

Oliguria is defined as the production of a decreased amount of urine. This can be defined as a daily urine production of less than 400 mL. Normal urine production is between 1,200 to 1,500 mL and it can range from 600 to 2,000 mL. Isostenuria is a condition that produces urine with a specific gravity of 1.010 due to impaired renal tubular function. Diabetes mellitus produces urine volumes of >2,500 mL/day.

When collecting a specimen for a blood alcohol test, why should tincture of iodine NOT be used to cleanse the venipuncture site? - Because it is a disinfectant, not an antiseptic and is not meant to be used on the skin. - Because is not a powerful enough antiseptic to properly cleanse the collection area. - Because it contains alcohol. - Because is only available in powdered form not liquid form.

Tincture of iodine is a liquid disinfectant commonly used to cleanse patient's skin during the venipuncture procedure. It contains alcohol and if used, it could interfere with the test results by falsely increasing the blood alcohol level.