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The type of isolation category that always requires a HEPA mask or respirator to be worn is:
India ink can aid in the visualization of the polysacchride capsules of yeast such as Cryptococcus neoformans.
Micro
India Ink is used to:
Which of these advancements in the clinical laboratory has led to concerns about patient privacy
Match each of the descriptions with the appropriate magnification:
1. Color, Rouleau, Overall Slide Quality, Cell Distribution
2. Platelet estimates RBC-platelet-WBC morphology WBC differential RBC inclusions
3. Select area to examine, WBC estimate
This type of laboratory testing provides immediate assessment of the patient and can be performed at their bedside:
Serum amylase and lipase levels may be slightly elevated in chronic pancreatitis, but not diagnostic enough to predict chronic pancreatitis; wheras high levels are found only during acute pancreatitis episodes. In the later stages of chronic pancreatitis, normal to decreased levels of amylase and lipase are caused by the gradual inability of the pancreas to secrete the enzyme
All of the statements below regarding amylase and lipase in pancreatitis are TRUE EXCEPT:
The Clinical Laboratory and Standards Institure (CLSI) recommends that all patient specimens are delivered to the laboratory no more than 2 hours after collection to reduce pre-examination variables caused by cellular action and the effects of prolonged exposure of specimens to room temperatures, such as:
Question options:
The correct answer which best fits the characteristics in this question is Mycobacterium kansasii.
The remaining Mycobacterium strains can be elimated as:
Mycobacterium marinum is considered a fast-grower.
Mycobacterium scrofulaceum produce deep-yellow to orange pigmented colonies when grown in the either the light or dark.
Mycobacterium avium grows colonies which are nonpigmented in the light and dark which do not intensify after light exposure.
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
development of yellow pigment upon exposure to light
Anything that can cause significant turbidity in a blood sample, such as high leukocyte count or lipemia can potentially interfere with the accuracy of a spectrophotometric hemoglobin assay.
Hematology
Which of the following may interfere with the accurate measurement of hemoglobin:
A young man is experiencing difficult breathing after fainting. The physician orders a blood gas analysis which shows the following results:
pH = 7.25
pCO2 = 62 mmHg
pO2 = 70 mmHg
HCO3 = 23 mEq/L
Which condition is most likely afflicting this patient?
Hemoglobin electrophoresis uses an electric field to separate hemoglobin molecules based on differences in net electrical charge. The rate of electrophoretic migration is also dependent on the ionic radius of the molecule, the viscosity of the solution through which it is migrating, the electrical field strength, temperature, and the type of supporting medium used.
Electrophoretic separation of hemoglobin fundamentally relies on:
Skeletal deformations result from the increased erythropoiesis that occurs in beta thalassemia major. Children with beta thalassemia intermedia may demonstrate some facial bone deformity, however this is not common. Beta thalassemia minor rarely causes any physical signs or symptoms and beta thalassemia minima is completely asymptomatic.
Skeletal deformations are most commonly present in which of the following beta thalassemias?
Platelets do not circulate in inactivated, spiny forms. The spiny, sticky form of the platelet is initiated once the platelets become activated in response to blood vessel damage.
Which of the following is not true in terms of platelet characteristics?
Insulin is the hormone that is mainly responsible for the entry of glucose into the cell for energy production
Glucagon and epinephrine promote glycogenolysis, conversion of glycogen to glucose, which increases plasma glucose. Cortisol, along with glucagon, increases gluconeogenesis, formation of glucose from noncarbohydrates, which also raises plasma glucose concentration.
Chemistry
Which of the following hormones is mainly responsible for the entry of glucose into the cell for energy production?
The dematiaceous molds can be broadly separated into two major groups: the agents of chromomycosis that grow more slowly, maturing only after 7 days or more of incubation, and the more rapidly growing species that most commonly are clinically insignificant commensals or contaminants when recovered from clinical specimens, but in rare situations may cause opportunistic infections called phaeohyphomycosis.
Dematiaceous molds can be broadly separated into two major groups; the agents of chromomycosis and clinically insignificant commensals or contaminants. The agents of chromomycosis grow: more slowly than; more rapidly than; or generally at the same rate as the clinically insignificant commensals or contaminants?
In which disorder do neonates demonstrate the presence of Bart's hemoglobin that changes to beta chain tetramers in adults?
The term that is used to describe the color in these tubes of CSF is "xanthochromia." Xanthochromia is an abnormal color, usually yellow, orange, or pink, in the supernatant of the CSF sample. It may indicate that a subarachnoid hemorrhage (SAH) has occurred.
Jaundice and icterus both describe a yellowing of the skin, mucous membranes, and eyes. Blood plasma/serum that is deep yellow is also described as icteric.
What term is used to describe the color in these tubes of cerebrospinal fluid (CSF)?
The role of the point-of-care testing (POCT) compared with in-laboratory testing is the
The agency within Department of Health and Human Services (DHHS) responsible for implementing CLIA'88 is:
Which one of the following conditions is NOT associated with hereditary spherocytosis?
Which advancement in clinical science occurred during the second half of the twentieth century?
Yellow stopper tubes are used for all of the following except:
Question options:
Though automated extraction machines have many benefits over manual methods the costs are high and generally require a high throughput of samples in order to justify the costs.
Automated extraction has many benefits over the traditional manual methods. The most important benefit is that the nucleic acid isolated is constantly consistent. There is a reduced amount of manipulation with dramatically decreases the chance of cross contamination. Also, automated extraction machines are considered moderate complexity and can be performed by a wider variety of laboratory professionals.
All of the following are considered benefits of automated isolation and extraction equipment EXCEPT:
n reporting out Gram stains, one should not go beyond what objective observation will allow. In this case, bacterial cells are observed, which are spherical and gram-positive. Their arrangement in tetrads and clusters might be helpful to the physician, suggesting staphylococci. However, one should stop short of naming staphylococci in an official report, as the large gram-positive cocci in tetrads is also suggestive of Micrococcus species, for which human infections have not been reported.
A Gram stain of the serous exudate is shown in the image. The appropriate report would read:
Prozone effect (due to antibody excess) will result in an initial false negative in spite of the large amount of antibody in the serum, followed by a positive result as the specimen is diluted.
The prozone effect ( when performing a screening titer) is most likely to result in:
Measuring the turnaround times of troponin tests from the emergency department would provide valuable information. This data represents circumstances in which patient safety may be compromised if results are delayed and treatment is not started as soon as possible.
A laboratory manager wants to evaluate the timeliness of patient services in order to prevent medical errors caused by delay in treatment. Measuring the turnaround time for which of these analytes would provide the most valuable information?
Lipids tend to form a "maltese cross" pattern when viewed in polarized light, which helps to differentiate them from other urine microscopic components.
Substances found in urinary sediment that are more easily distinguished by use of polarized microscope are:
The structures involved in the production of semen include the prostate, the seminal vesicles, and the bulbourethral gland, along with the testes and epididymis.
Semen is produced as a combination of secretions from the different regions of the male reproductive tract. Each fraction differs in chemical composition and function.
Spermatozoa are produced in the testes. They mature in the epididymis. The testes also produce testosterone and inhibin.
Fluid from the seminal vesicles accounts for approximately 70% of semen volume. The seminal vesicles are the source of fructose in semen. Fructose is used by the spermatozoa as an energy source.
The prostate gland supplies about 20% of the volume of semen. Its fluids include acid phosphatase and proteolytic enzymes that lead to coagulation and subsequent liquefaction of semen. The prostate also contains most of the IgA found in semen.
The bulbourethral gland produces mucoproteins that make up about 5% of the volume of semen.
The pituitary gland is not directly involved in the production of semen; instead hormones are released which stimulate the production of sperm. The urethra is not involved in the production of semen.
Which of the following are directly involved in the production of semen?
In which of the following laboratory situations is a verbal report permissible?
The ApoB/ApoA1 ratio has a positive risk marker (ApoB-100) and a negative risk marker (ApoA1). Risk diminishes as ApoA1 goes up (a negative marker) and risk increases in proportion to ApoB concentrations (a positive risk marker). This 'double-edged sword' provides good risk prediction. The other risk markers in question do not have this dual-advantage.
Which risk marker has both positive and negative cardiovascular risk integrated into its measurement?
The A and B antigens are present on the red cells of an AB patient. H antigen is a precursor to the ABO antigens.
An individual with type AB blood will demonstrate the complete absence of which of the following antigen sites?
Gram-positive bacteria retain the primary crystal violet stain that is applied in the Gram stain because of the cross-linking of the thick peptidoglycan layer in their cell walls. Their cell walls contain less lipids than that of a gram-negative bacteria, and this reduces the permeability of their cell wall to the organic solvents that are used as a decolorizer. When the counterstain is added, it may enter the gram-positive cell, but does not change the color of the cells.
A thick peptidoglycan is MOST often associated with which of the following types of bacteria?
Angiotensin is an oligopeptide in the blood that causes vasoconstriction, increased blood pressure, and release of aldosterone from the adrenals.
A major action of angiotensin II is:
Blood Bank; Immunology
Which of the following best describes the primary function of antibodies:
First, determine the number of WBC's from the hemocytometer as follows:
WBC count = (dilution ratio x # of cells counted x 10) / (# mm2 area counted)
Then: WBC count = (20 x 100 x 10) / (8) = 2500 WBC/mm3 (or 2500 WBC/uL or 2.5 x 103 WBC/uL)
Next, to find the WBC count per liter, multiply the WBC count/uL by the number of uL/L (there are 106 uL/L)
So: (2.5 x 103 WBC/uL) x (106 uL/L) = 2.5 x 109 WBC/L
Hematology
A 1:20 dilution is made for a manual WBC count. The four corner squares on both sides of a hemocytometer are counted. A TOTAL of 100 cells are counted in that area. What is the white blood cell count in terms of a liter (? x 10^9/L)?
The recommended order of draw for a complete blood count (CBC), prothrombin time, and cholesterol is:
A casual blood glucose >/= 200 mg/dL on a patient with symptoms and an A1C >/= 6.5% meet diagnostic criteria for diabetes.
Chemistry
A physician is evaluating a 45-year-old obese male for diabetes and orders a plasma glucose at time of evaluation and a HbA1C one week later. The patient has a family history of diabetes and currently exhibits symptoms of diabetes.
What would be the best course of action if these are the blood glucose results?
Casual Blood Glucose: 208 mg/dL
HbA1C one week later: 7.2%
The parents will each give one of their ABO genes, so the possibilities are as follows:
AB, AO, AB, AO = 50% chance of A blood type, 50% chance of AB blood type
Blood Bank
If parents have the blood group genotypes AA and BO, what is the possibility of having a child with a blood type of A?
If all newborns were tested, many positive DATs due to ABO incompatibility would be detected that are of no clinical significance.
Although many laboratories test infants born to group O Rh positive females due to the higher risk of ABO HDFN when the mother is group O, testing such infants is optional provided there is appropriate monitoring and follow-up for hyperbilirubinemia.
Blood Bank
Not performing direct antiglobulin tests (DATs) on newborns born to group O Rh positive mothers is acceptable good practice, providing there is appropriate surveillance and follow-up to detect hyperbilirubinemia.
Darkfield microscopy allows a lower limit of resolution than bright-field microscopy which helps the tiny spirochetes to be seen in patient samples. In darkfield microscpy, there is a dark background where directly transmitted light is excluded by a dark-field condenser allowing only scattered light to be focused on the specimen. With dark-field microscopy bacteria appear luminous against a dark background.
Which of the following microscopic techniques is best suited for direct examination of the infectious agent of syphilis?
Allergen-specific IgE, synthesized in response to allergens, becomes fixed to receptors on cellular membranes, especially those of basophils. If these receptor-bound IgE molecules are aggregated on re-exposure to specific allergen, both mast cells and basophils produce mediators that result in the allergic response. IgE-antigen interaction at the cell surface causes degranulation of cells and release of substances including: histamine, SRS-A, platelet activator, a kallikrein, and an eosinophil chemotactic factor. Basophils are the principal cells that bind IgE antibody while their number of receptor sites is proportional to serum IgE levels. Eosinophils are drawn to the site by the basophil chemotaxis mechanism, but are not the main cell which binds the IgE antibody.
Immunology
The mediator cells that bind MOST to IgE antibodies are:
21 CFR 606.65 states, "Supplies and reagents shall be used in a manner consistent with instructions provided by the manufacturer."
The correct answer is A. The reagents must be used according to the manufacturer's instructions for use. If the instructions say one or two drops may be used and the facility procedures also allow one or two drops, then there is no problem with the staff members choosing to use two drops.
While equipment must be calibrated, it does not generally influence the number of drops used.
Staff members often ask co-workers and colleagues from other facilities how to perform tasks, but it is the manufacturer's instructions for the operation of equipment and the use of reagents that must be followed.
A laboratory employee who is performing an internal audit of routine ABO and Rh typing procedures notes that a technologist places two drops of Anti-D in a tube, centrifuges the tube for 20 seconds, and reads the reaction using a magnifying mirror. When questioned about the procedure, the technologist indicates that most staff use two drops of Anti-D reagent because the reactions are stronger with two drops. In addition to reviewing the facility procedure manual, what should be done to ensure regulatory compliance?
To obtain a serum sample for a stat test on a patient receiving anticoagulant therapy, the recommended tube is:
Question options:
Though automated extraction machines have many benefits over manual methods the costs are high and generally require a high throughput of samples in order to justify the costs.
Automated extraction has many benefits over the traditional manual methods. The most important benefit is that the nucleic acid isolated is constantly consistent. There is a reduced amount of manipulation with dramatically decreases the chance of cross contamination. Also, automated extraction machines are considered moderate complexity and can be performed by a wider variety of laboratory professionals.
All of the following are considered benefits of automated isolation and extraction equipment EXCEPT:
VLDL transports endogenous lipids, whereas chylomicrons transport exogenous (dietary) lipids. Cholesterol is transported by HDL and LDL.
The function of the very low density lipoproteins (VLDL) is to transport:
Match the viruses below with their associated conditions.
1. Herpesvirus
2. Papovavirus
3. Rhinovirus
4. Rotavirus
Estriol levels in conjunction with hCG and AFP can be obtained during pregnancy to:
A laboratory scientist is working the night shift at a local hospital when the power goes out. What is the course of action to continue to provide laboratory results?
The presence of hyaline, septate hyphae, and a young conidiophore with a foot cell and a swollen vesicle in a fungus culture are excellent clues indicative of Aspergillus. Aspergillus has the ability to infect primarily immunocompromised hosts, and causes pneumonia and/or disseminates to other organs. Clinical specimens should be inoculated onto primary isolation media, such as Sabouraud's dextrose agar. Aspergillus spp. are fast growing and can be white, yellow, yellow-brown, brown to black or green in color.
The presence of hyaline, septate hyphae, and a young conidiophore with a foot cell and a swollen vesicle in a fungus culture are excellent clues indicative of:
Fibers can be mistaken for casts on occasion, especially hyaline casts. Fibers, however, are usually thinner and appear less uniform in structure than casts do.
Urinalysis & Other Body Fluids
Which of the following artifacts may be mistaken for casts?
Ferritin and hemosiderin are considered storage forms of iron.
Which substance(s) is/are considered iron storage compounds?
DAT ( Direct Antiglobulin Test ).
When AHG or Coombs serum is used to demonstrate that red cells are antibody coated in vivo, the procedure is termed:
Bacterial contamination can manifest itself in several ways including: the presence of clots, darker purple-black color of blood unit, unit can appear cloudy, hemolysis may be present.
During routine inspection, a unit of unexpired blood was noticed to have a black color with numerous small clots. What is the likely cause for this observation?
Which of the following organizations has developed standards to maintain the performance of the clinical laboratory at the highest standards for quality care?
Hemolytic transfusion reactions seldom occur because the incidence of unexpected antibodies in random patients is relatively low, e.g., 3-5% is sometimes cited.
Being transfused with O Rh negative RBC is irrelvant if you have an unexpected antibody like anti-K or anti-c.
Incompatible red cells may "bleed out" but only if bleeding is brisk. Even then, a hemolytic reaction may occur later once the patient's antibody rebounds and destroys remaining antigen-positive donor red cells.
It's true that some patients have only cold-reactive antibodies that will not react at body temperature. But this does not explain why warm-reactive red cell antibodies cause few reactions
Why do so few patients transfused with un-crossmatched red cells in an emergency experience a hemolytic transfusion reaction? Select the one best reason.
Oxalate, EDTA, and citrate are anticoagulants that inhibit clot formation.
Which of the following blood additives is most useful for serum collection:
This scenario's answer can be calculated by first deciding what the total quality control labor costs are as well as what the total consumable costs are. In this case, if quality control is run 3 times per day, a total of 1095 quality control runs are performed each year. The direct labor cost of $2.63 multiplied by 1095 quality control runs equals $2879.85 per year in quality control direct labor. The hospital pays $354.00 per month on quality control consumables, which equals $4248.00 per year. The total quality control costs in a year are equal to $2879.85 + $4248.00 = $7127.85. If 76,000 new chemistry tests panels are peformed each year, the total quality control cost per new chemistry test panel will be $0.09.
General Hospital is considering the addition of a new chemistry panel containing 12 tests. The laboratory is asked to calculate the total cost of quality control per new chemistry test panel. Quality control must be performed 3 times per day (every 8 hours). The labor cost per quality control test for this panel is $2.63. A month's worth of quality control reagent costs $354.00. What is the total quality control cost per new chemistry test panel if 76,000 of these new panels are performed each year?
Animals serve as a reservoir of infection" is the correct answer because Shigella only infects humans while Salmonella is found in many animals. Both have diarrhea as the major symptom. Endotoxin is produced by all gram negative bacteria and exotoxin is only produced by Shigella.
A major difference between Salmonella enterica and Shigella infections is that only in salmonellosis can:
Which of the following organizations now provides the certification exam for laboratory professionals?
RAST tests, or Radioallergosorbent tests, are used to screen for an allergy to a specific substance or substances if a person presents with allergy-like symptoms.
The assay which is most helpful in identifying specific allergens is:
Monoclonal antibodies are monospecific antibodies that are the same because they are made by one type of immune cell which are all clones of a unique parent cell, also called a hybrid cell line, which usually arise from a hybridoma. The fusion of a specific antibody-producing lymphocyte with a myeloma cell will multiply to become a source of pure monoclonal antibody. This is often used in the manufacturing process for monoclonal antibody reagents.
Monoclonal antibodies are usually manufactured in vitro by using:
Alpha-fetoprotein is a substance typically used in the triple test during pregnancy and for screening chronic liver disease patients for hepatocellular carcinoma.
Increased concentrations of alpha-fetoprotein (AFP) in adults are MOST characteristically associated with:
The liver is the primary target organ for the Hepatitis B virus (HBV). The inflammation caused by HBV can result in permanent liver damage, including cirrhosis, liver failure, and even hepatocellular carcinoma.
What is the primary target of the Hepatitis B virus?
Myoglobin rises typically within 2-4 hours after a myocardial infarction and stay elevated for days, with a peak at the 6-9-hour mark post-MI. After myoglobin, troponin is the next fastest to rise afer a mycardial infarction and can rise within 3-4 hours with a peak around 12 hours post-MI. LD (8-12 hours, 24-48 hour peak) and CK (4-6 hours with peak at 24-36 hours) will also rise after MI, but are not as fast to rise as myoglobin and troponin.
Chemistry
A patient is admitted to the hospital with acute chest pain, but which of the following cardiac markers will be elevated FIRST if the patient had an MI?
High-sensitivity C-reactive protein (hs-CRP) is used as an aid in the diagnosis and treatment of cardiovascular disease (CVD). At low levels, it can detect those at risk for cardiac heart disease. At high levels in those with no history of heart disease, it indicates a high risk for acute myocardial infarction (AMI), stroke, or peripheral vascular disease. For patients with acute coronary syndrome (ACS) or stable coronary disease, hs-CRP is used to predict future coronary events.
Ranges of hs-CRP in prediction of risk for CVD are:
<1.0 mg/L Low CVD risk
1.0-3.0 mg/L Average risk for CVD
>3.0 mg/L High risk for future CVD
If results are >10.0 mg/L, the patient should be evaluated for an acute inflammatory condition.
Chemistry
A high-sensitivity C-reactive protein (hs-CRP) test result of 5 mg/L (normal = < 1 mg/L) may indicate which of the following?
In an alkaline medium, potassium ferricyanide oxidizes hemoglobin to methemoglobin. Further reaction with potassium cyanide produces cyanmethemoglobin which has a maximum absorbance at 540 nm. Color intensity is proportional to total hemoglobin concentration, which is how the hemoglobin levels are measured.
Hematology
In the hemoglobin methodology using potassium ferricyanide the following measurable reaction occurs:
Isolation and detection of Gardnerella vaginalis from vaginal secretions is improved by which of the following?
Fusarium species is the most likely associated with mycotic keratitis.
Trichophyton rubrum is a dermatophyte that commonly causes an itching, scaling skin infection of the feet, known as tinea pedis. Scedosporium apiospermum is commonly associated with sinusitis. Aspergillus niger typically causes otitis externa and can also be associated with sinusitis.
Which of the following species or organisms is the most likely to be the cause of mycotic keratitis (fungal eye infection)?
Hemolytic anemia, myelodysplasia, and liver disease may each fit this peripheral blood picture. Each of these conditions can display peripheral blood macrocytosis. It is easy to observe the overall larger size of the red blood cells in this image compared to the normal lymphocyte also present.
When macrocytes are present, they should be examined for their shape (round vs. oval), the hemoglobin content (central pallor), and whether or not there are any inclusions present in the cell.
Iron deficiency would not be the correct answer in this case, since this condition is associated with microcytosis instead.
The complete blood count was obtained from a patient recently admitted to the emergency room. The red blood cell indices obtained revealed an MCV of 115 femtoliters (fL) (normal range 80 - 90 fL). The patient met the criteria for a peripheral blood smear examination. A representative field is shown on the right.
Which of the following conditions may be indicated by the results seen on this peripheral blood smear?
Which of the following Rh antigens is found the highest frequency in the Caucasian population:
Vitamin K is needed to produce certain coagulation factors, in particular factors II, VII, IX, and X. Deficiencies in these factors can lead to increased clotting times and can cause hemorrhagic disease.
A deficiency in which of these vitamins leads to increased clotting time and may result in hemorrhagic disease?
Match each of the following:
1. Ratio of cellular area to total area in the bone marrow section.
2. Number of myeloid cells compared to nucleated erythroid cells.
3. Use low power to estimate their quantity and appearance.
4. Use Perls' Prussian blue stain.
This patient is most likely suffering from an immediate-acting coagulation inhibitor; most commonly, lupus anticoagulant. Notice that the addition of normal pooled plasma does not correct upon initial or incubated mix, which means that the inhibitor is not time or temperature-dependent.
Factor VIII is not the correct answer as a factor deficiency would have corrected upon the addition of normal pooled plasma. Factor VII is not the correct answer, as the aPTT assay does not account for factor VII activity or concentration.
The laboratorian completed the mixing study ordered for John Doe. The results are as follows:
Initial aPTT result: 167 seconds
Initial 1:1 Mix with Normal Pooled Plasma: 158 seconds
Incubated 1:1 Mix with Normal Pooled Plasma: 150 seconds
Which of the choices below would most likely explain the results for this patient?
TESTED 21 Nov 2024