Clin Lab Flashcards
1
Q
Which of the following values would be consistent with hyponatremia?
A
Na+ <135
2
Q
A patient has a potassium of 6.5. This would be consistent with which of the following?
A
Hyperkalemia, risk of fatal cardiac arrythmia.
3
Q
Which of the following represents the normal range of hemoglobin in a male?
A
14-18
4
Q
Which of the following is an example of a threshold value?
A
There will only be one value
5
Q
Which of the following describes prevalence?
A
The # of people w/ the disease at a specific time.
6
Q
A cutoff for a lab test is set so that all people with the disease are identified, therefore a negative test does help rule out the disease. Therefore, this lab would have high____
A
sensitivity
7
Q
Which of the following tests measures the % of RBCs in the total volume of blood tested?
A
hematocrit
8
Q
Which of the following accurately describes diascopy
A
using a glass slide to assess any red lesions for blanchability
9
Q
- Which diagnostic imaging modality utilizes a series of rapid x-rays taken from one angle that form a video?
A
Fluoroscopy
10
Q
- Which of the following tests are commonly used in microbiology diagnostics?
A
Stain, Culture& ID, Antimicrobial sensitivity testing
(other test that uses microbes: chem testsantigen/antibody test)
(Molecular/Genetic tests RNA/DNA testing)
11
Q
A test involves the detection of antigens for a bacteria in which the binding of specific antibodies to the antigens causes a color change. This is an example of what type of test?
A
ELISA
12
Q
Which of the following tests is used in the diagnosis of sickle cell anemia?
A
electrophoresis
13
Q
- Which of the following best describes the indication for using a Wood’s lamp?
A
When a fungal infection is suspected (can tell us about pseudomonas infections)
14
Q
Which of the following should be considered before ordering a diagnostic test?
A
Purpose, result in timely fashion, harm of false (+) & (-), cost effective, risk, invasive?, special prep for test, FU?
15
Q
Which of the following labs is part of a BMP (basic metabolic panel)?
A
Ca++, Na+, K+, Cl-, CO2, BUN, Cr, Glucose, (Anion Gap), (GFR)
16
Q
A patient presents with a pruritic rash under her abdominal pannus and under her breasts. She recently completed a course of ciprofloxacin for a urinary tract infection. Which of the following tests would be most likely to help confirm the diagnosis?
A
KOH prep test
17
Q
A patient comes to the clinic with complaints of muscle weakness. On examination, you note significantly increased reflexes. Which of the following would be expected on a BMP (basic metabolic panel)?
A
Decreased Calcium/hypocalcemia
18
Q
A patient comes to the clinic with a macular rash. On physical exam, you note a negative diascopy exam. Which of the following is the most likely underlying cause of the rash?
A
Hemorrhagic issue
19
Q
A new strain of the MERS virus has emerged and is making people very sick with severe respiratory symptoms. A new diagnostic test is under development to try and identify anyone who potentially has the virus, so that people who test negative can continue to come to school / work. Which of the following would be correct about this test?
A
a sensitive test
20
Q
Gram stain is used for?
A
Used to differentiate Gram (+) and Gram (-) bacteria
21
Q
Acid fast stain is used for?
A
- Used on things that have atypical cell walls
- Mycobacteria and Nocardia
22
Q
India ink stain is used for?
A
- “negative” stain
- Used on organisms that have capsule
- Cryptococcus
23
Q
Calcofluor white stain is used for?
A
- Fluorescent stain used for fungi
24
Q
List some examples of microorganisms that show up well with India ink stain
A
- Cryptococcus
25
List examples of bacteria stained with acid fast stain.
- Mycobacteria
- Nocardia
26
Explain the difference in cell membrane structure in Gram negative versus Gram positive bacteria
- Gram (+) have a thick peptidoglycan wall purple
- Gram (-) have a thin peptidoglycan wall and have an outer membrane pink
27
What sites in the body should be sterile?
- LRT (bronchoscopy or bronchioalveolar lavage)
- Blood (tend to be septic)
- CSF (meningitis/encephalitis)
- Pericardial fluid
- Pleural fluid
- Peritoneal fluid
- Synovial fluid (considered medical emergency b/c it can degrade joint)
- Bone
- Urine (bladder/kidney) (true sterile--> used catheter)
28
Explain how MacConkey agar and EMB agar distinguish between bacteria
- MacConkey will turn Lactose fermenters(pink) & non lactase fermenters (yellow)
- EMB will turn Lactose fermenters (dark green) (E. coli-->metallic green) Enterobacter (purple)& non lactase fermenter (yellow)
29
List Lactose-fermenting Gram-negative bacteria that would turn MacConkey agar pink and would have green colonies on EMB agar.
- E. coli, Klebsiella, Enterobacter
30
List Lactose non-fermenting Gram negative bacteria that would turn MacConkey agar yellow and would have yellow colonies on EMB agar.
- Pseudomonas, Proteus, Salmonella
31
Explain how sheep blood agar distinguishes between types of Streptococcus.
- Alpha
- Beta
- Gamma
32
Explain how catalase is used to differentiate Streptococcus from Staphylococcus
- Staph--> gram (+) catalase (+)
- Strep--> gram (+) catalase (-)
33
Explain how serology testing is done, and what indicates a result that supports diagnosis of an infection
Take a blood sample from the patient and you want to test the presence of antibodies. You can see a 4-fold increase in two samples that are two weeks apart
34
Describe the differences in primary versus secondary antibody response to infections
The primary response is smaller reactions of IgM and with the secondary antibody response you have a higher and quicker IgG response because of memory.
35
Describe what acute phase reactants are, and list examples
- The PROs whose concentration will either increase or decrease due to inflammatory response or process of inflammation.
- Increased: CRP, ESR, Fibrinogen, Alpha-1-antitrypinsin, hepcidin, Procalcitonin
- Described: Albumin and transferrin
35
Explain what a titer is and how it is reported
- Do serial dilutions of the patient’s blood.
- Add antigens of the organism you are testing for to the dilutions.
- If the patient has the antibodies, it will change colors once it attaches to the antigen.
- You keep doing this until there is a well with no color change.
- The patient’s titer is the well right before the clear well.
- The will always be reported in a ratio. Example: 1:256.
36
Describe what CRP is and how it is used in clinical practice
- Non-specific inflammatory marker
- PROs bind w/ phosphocholine on pathogenic & damaged cells to activate complement & phagocytic cells. Used to monitor effectiveness of Tx
- Men--> and Women--> 1.6
37
Describe what ESR is and how it is used in clinical practice
- Non-specific inflammatory marker
- When inflammation occurs--> ^^ PROs (fibrinogen: acute phase reactant)--> causes rouleaux which settles faster than blood w/less rouleaux
38
Describe changes in CBC seen in the following:
- bacterial infections--> increased neutrophils; more banded neutrophils; increased WBC, vacuoles & granulations
- viral infections--> decreased WBC & increased lymphocytes
- parasite infections--> increased eosinophils
39
Gram positive cocci
- Strep,
- Staph
- Enterococcus
- Peptostreptococcus
40
Gram positive rods
- Bacillus
- Clostridium
- Clostridioides
- Corynebacterium, Listeria
41
Gram negative cocci
- Neisseria
- Moraxella
- Hemophilus
42
Gram negative rods
- Bacteroides, Bartonella, Bordetella, Brucella
- Campylobacter
- Enterobacter, Escherichia
- Francisella
- Klebsiella
- Legionella
- Pasteurella, Proteus, Pseudomonas
- Salmonella, Serratia, Shigella
- Vibrio
43
Gram variable bacteria
- Bacillus
- Clostridium
44
Anaerobic bacteria: gram (+)
- Clostridium
- Actinomyces
- Propionibacterium
- Peptostreptococcus
(Mouth bacteria)
45
Anaerobic bacteria: gram (-)
- Bacteroides
- Fusobacterium
- Campylobacter
- From hotdogs
- Prevotella
46
List two bacteria that are usually diagnosed with serology.
Brucella & Rickettsia
47
Sheep Blood Agar: strep pneumo
alpha--> green
48
Sheep Blood Agar: strep viridans
alpha--> green
49
Sheep Blood Agar: strep pyogenes
Group A Beta--> green w/ hemolysis
50
Sheep Blood Agar: strep agalactiae
Group B Beta--> green w/ hemolysis
51
Explain the appearance of a Clostridium perfringens infection on imaging
- Imaging may show gas in the tissues as dark circles
52
Explain the testing for C. diff?
- varies depending on toxin
- Glutamate dehydrogenase (GDH) antigen test
- PCR, Culture (GS)
53
Explain the testing for Legionella pneumo
- Urine Ag test
- PCR
- Culture (GS)
54
Explain the testing for Bartonella henselae?
- most times Clin Dx
- Culture or Serology
- PCR
55
Explain the testing for mycobacterium tuberculosis
Active
- Culture (GS)
- NAAT & acid-fast bacilli stain
Latent
- IGRA
- PPD aka TST
56
Explain the testing for Bordetella pertussis
- mostly Clin Dx,
- Culture or PCR (0-4 weeks)
- Serology (>4weeks)
56
Explain the testing for Borrelia burgdorferi
Serology (titers) & PCR (must do two separate tests) then
- Western Blot or ELISA
57
Explain the testing for Influenza
- Rapid antigen test (flu swab), HIGH specificity & low sensitivity
- PCR – HIGH specificity & sensitivity
58
Explain the testing for SARS-CoV 2
o NAAT/Rapid PCR HIGH specificity, low sensitivity
o Antigen test LOW specificity & sensitivity
59
Explain the testing for Human Herpes Virus 1 & 2 (HHV)
o Tzanck smear, culture, fluorescent Ab stain, PCR (from CSF), serology (rule out)
60
Explain the testing for * Epstein-Barr virus (HHV 4) – mononucleosis
o Heterophile antibodies (“monospot”)
61
Explain the testing for * Cytomegalovirus (HHV 5)
o Quantitative PCR
o CMV pp65 Antigen Test
62
Explain the testing for * Rabies testing
o Suspected infx multiple samples like blood, skin (posterior neck), saliva, CSF
o Screening RFFIT test
63
Explain the testing for * HIV testing
o Screening: 3rd gen or 4th gen (Ag & Ab)
o Acute: 4th gen (Ag & Ab) and HIV-1 RNA test
o HIV+ patients:
CD4 T- Lymphocyte Count
HIV-RNA quantification (viral load)
Phenotypic and Genotypic Assays for Antiretroviral Drug Resistance
64
Explain the criteria for a definitive diagnosis of a fungal infection
* ID the fungus Culture, DNA sequencing, or mass spectrometry
* Evidence of inflammation CRP, ESR, Elevated WBC count
65
Explain the role of beta-d-glucan testing for fungal infections
* Non-specific marker for fungal infections that detects Ag that is present in the cell wall of fungus.
* Sepsis can show up has elevated Beta-D-glucan
66
25. Explain how dermatophyte test media is used
* Normal is yellow, negative test is yellow, positive is magenta
67
Explain the testing for Sporothrix
- biopsy
- fluid sample
68
Explain the testing for Aspergillus
- culture
- histopathology
- serology (IgG Ab)
- Direct Ag (Beta-D-glucan or Galactomannan)
- Maldi-Tof
- Imaging is supportive
69
Explain the testing for Cryptococcus
- India ink stain
- Imaging (solid nodules)
- Culture (Biospy/blood/ CSF)
- Direct Antigen (Crypto Ag {specific, less sensitive (+) rules it in}),
- Image of lungs will show nodules
70
Explain the testing for Pneumocystis
- Imaging (bilateral lungs, near hilum)
- Antigen testing (Beta-D-glucan), - PCR
- Imaging “ground class” opacity (CT)
71
What does dimorphic fungi look like on imaging?
more nodular
72
What does a serology look for in dimorphic fungi?
antibodies
73
Which dimorphic fungi can have antibody testing?
- Paracoccidioidomycosis
- Coccidioidomycosis
- Histoplasmosis
74
Which dimorphic fungi can have antigen testing?
- Blastomycosis (serum)
- Histoplasmosis (serum/urine/BAL)
75
Describe which parasitic infections tend to cause ring-enhancing lesions on CT scans of the brain
Toxoplasmosis--> cat litter
75
Describe the manifestations of and testing for nematode infections
- 90% are asymptomatic, S/S: diarrhea, fever, blood stools
- Stool microscopy, Stool Ag testing, PCR, Supportive--> heme+ stool (hemoccult test)
75
What are the basic densities of tissues on x-rays and CTs, and what do they look like on imaging?
- Air--> darkest
- Fat--> a little gray
- Soft tissue--> bright gray
- Calcium--> bright
- Metal--> brightest
76
Describe which parasite infections tend to have associated eosinophilia.
- Toxocara
- Ascaris
- Strongyloides,
- Schistosomes
- Filaria
- Trichinella
- Necator
76
What are the types of contrast used with x-rays? What are the major possible adverse effects?
- Oral
- Barium (GI tract)
- Water Soluble (iodinated): X shellfish or iodine allergy
77
Describe the testing for Cryptosporidium
- Acid fast--> Stool staining (3 samples) or PCR
77
What are the risks, benefits, and limitations of x-rays?
- Risks: Radiation exposure (lifetime exposure)
- Benefits: Easy, Fast, Widely available, Cheap
- Limitations: Hard to see soft tissue, Need multiple view for 3-
78
Describe what a Hounsfield unit is, and give typical Hounsfield units (HU) for the following:
- Each image = thousands of pixels
- Bright white or dark black
- Each pixel is assigned a Hounsfield unit based on attenuation
* air: -1000 HU
* water: 0 HU
* bone: +400 - +1000
* organs and fat: +20 - +10
78
What are the three windows for a CT chest?
- Mediastinal or soft tissue
- lung
- bone
79
Describe the types of contrast used with CT scans and give indications to use or not use contrast
- Water soluble (iodinated)
- To use: enhance soft tissue, GI tract, & BVs
- Not to use: Active bleeding, stones, acute kidney failure, don’t used for fracture
80
Describe the differences between T1 and T2 images
- T1 is shorter interval; Fat shows bright
- T2 is longer interval; Fat & water are bright
- T2 – T1 to show just water and this will be indicative of inflammation & damaged cells
81
What view do you use for a broken nose on x-ray?
nasal bone series
81
C spine x- ray: AP view shows
C4 - C7
81
C spine x- ray: Oblique view shows
can see more space b/t the vertebrae (facet) where nerves come out
81
Describe the risks, benefits, and limitations of MRI scans
- Risks: nephrogenic systemic fibrosis (body turns to rock) w/ contrast
- Benefits: no radiation, good visualization of NS & tendons/ligaments
- Limitation: take long time, costly, size, less readily available-
81
What view do you use for maxillary sinuses on x-ray?
water's view (PA view)
81
What view do you use for frontal sinuses on x-ray?
Caldwell view (PA view)
82
Describe the level of echogenicity seen with different types of tissues, and describe the appearance on the ultrasound image
- Fluids – dark area on screen – ANECHOIC
- Bone – bright area on screen w/ shadow beyond – HYPERCHOIC
- Soft tissue – gray area – ISOCHOIC
- B/t the isochoic and anechoic is HYPOCHOIC
83
CT maxillofacial w/o contract is good for?
trauma
83
What view do you use for metal fragments or orbital floor fracture on x-ray?
orbital view
83
C spine x- ray: lateral view shows
C1 - C7
83
Which x-ray imaging view is good for abscess?
lateral soft tissue neck
84
CT maxillofacial w/ contrast is good for?
sinuses, chronic sinusitis
84
C spine x- ray: odontoid view shows
atlas & axis (C1 & C2)
85
CT neck w/o contrast is good for?
masses/swelling, hoarseness, dysphagia, stridor
85
Describe the differences on ultrasound between cellulitis and abscess
- Cellulitis--> cobblestoning
- Abscess--> dark area w/ pus (will be darker)
85
CTA neck is good for?
BVs
86
Describe the indications for nasal and sinus endoscopy
Indications:
- Chronic illness
- Chronic difficulty w/ air flow
- chronic epistaxis
- chronic HA
86
Describe the contraindications for nasal and sinus endoscopy
- Contraindications: Trauma, Intracranial infection, bleeding disorder or on blood thinners
87
Normal pressure of the eye?
10 to 20 mmHg
87
Which is worse an alkalotic chemical or acidic chemical & what is the target pH for the eye
- Alkalotic
- 7.0 to 7.3
88
Abnormal pressure of the eye?
>20 mmHg
88
Neutrophils Relative Normal
54 - 62%
89
Total RBC Count
4.7 - 6.1 x 10^6 (males)
4.2 - 5.4 x 10^6 (females)
90
Causes of polycythemia.
- high altitudes or chronic hypoxia (smokers)
90
Causes of anemia.
- iron deficiency, vitamin d deficiency, sickle cell
90
Causes of Leukocytosis.
- >/= 11
- sometimes bacterial infx (#s high & have symptoms) or Myeloproliferative disorder
91
Hematocrit
42 - 52% (males)
37 - 47% (females)
91
Hemoglobin
14 - 18 (males)
12 - 16 (females)
92
Causes of leukopenia.
- Viral infx
- Severe bacterial infx
- Autoimmune disorders, drugs, aplastic anemia
92
Total WBC Count
4.5 - 11 x 10^3
93
Lymphocytes Relative Normal
25 - 33%
93
Monocytes Relative Normal
3 - 7%
94
Eosinophils Relative Normal
1 - 3%
94
Lymphocytes Absolute Normal
1000 - 4000
94
Monocytes Absolute Normal
200 - 800
94
Basophils Relative Normal
0 -1%
94
Neutrophils Absolute Normal
2000 - 8000
95
Basophils Absolute Normal
0 - 400
95
Platelet Count Normal
150,000 - 450,000
95
Eosinophil Absolute Normal
100 -400
96
Is thrombocytosis concerning in most cases?
No
>450,000
97
Causes for thrombocytopenia.
< 150,000
- Autoimmune or liver issues
- can mess w/ clotting & bleeding problems
- surgeons like it above 150,000
98
What platelet level can cause spontaneous bleeds?
< 20,000
98
Sodium Normal Range
135 - 145
99
What does hyponatremia cause?
- muscle weakness & seizures
- we worry about neurons not working
100
Causes of hyponatremia
- dehydration
101
Causes of hypernatremia.
- dehydration
102
Hypernatremia can cause?
- obtunded
103
Which hypokalemia value is considered toxic?
< 2.5
103
Potassium Normal Range
3.5 - 5.0
103
Which hyperkalemia value is considered toxic?
> 6
104
Chloride Normal Range
95 - 110
104
Which two values are similar?
Na+ & Cl-
- pay attention when one is abnormal & the other isn't
104
Causes of hypocapnia.
ketoacidosis
104
Carbon Dioxide Normal Range
22 - 30
104
Causes of hypercapnia
COPD
105
Calcium Normal Range
8.4 - 10.2
106
Hypocalcemia causes...
- hyperexcitability (twitching, tetany)
107
Hypercalcemia causes...
- neuromuscular depression (hypoflexia)
108
What controls Ca++ levels in the blood?
Parathyroid Hormone
109
Magnesium Normal Range
1.6 - 2.6
109
Hypomagnesemia causes...
- incr excitability (twitching)
110
Hypermagnesemia causes...
- depress muscle excitability (hypoflexia)
111
___ & ____ imbalances have similar presentations.
Ca++ & Mg++
112
What is given to pregnant women to induce labor?
- Mg++
113
Which adult levels are similar in pediatric normal values?
- Na+
- Cl-
- Mg++
114
Which peds normal levels have a slightly wider range than adults and why?
- Ca++ & Phosphorus
- increased bone deposition
115
Describe peds potassium levels.
- K+ levels are normal in children < 1yo due to decreased urinary K+ excretion
- newborns may have incr turnover of RBCs
116
BUN Normal Range
5 - 20
116
Azotemia (> 20 BUN) symptoms
- no symptoms
116
Uremia symptoms
- azotemia + symptoms
- itching, flaky deposits on skin, confusion, fatigue
117
Are low BUN levels clinically significant?
No
117
Creatinine Normal Range
0.5 - 1.5
117
^ BUN & Cr ^ is likely due to?
- renal causes
118
^ BUN & normal Cr is likely due to?
- GI bleed (nonrenal)
119
What pediatric normals are similar to adult normals?
- Na++
- Cl-
- Mg+
120
Which pediatric normals have a slightly wider range than adults due to increase bone desposition?
Ca+
P
121
Describe K+ levels for pediatrics
higher K+ is normal in children less than 1yo due to decreased urinary K+ excretion
- newborns also may have increase turnover of RBCs
122
Electrolytes that may require separate orders?
- phosphorus
- magnesium
- serum osmolality
