LABORATORY TESTS Flashcards by Armani Yulong

It is a test for Steatorrhea

Test for Fecal Fat

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the presence of increase fats in
stool

Steatorrhea

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Fecal characteristic of Steatorrhea

Greasy; foul odor; spongy consistency

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Fecal volume of Steatorrhea

Increased

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Causes of Steatorrhea

Pancreatic insufficiency
Malabsorption, Maldigestion
Absence of bile

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inadequate intestinal absorption of processed foodstuffs despite normal digestive ability

MALABSORPTION

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an inability to convert foodstuffs
in the gastrointestinal tract into readily absorbable substances

MALDIGESTION

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Qualitative Fecal Fat Stain

Neutral Fat Stain
Split Fat Stain

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Stain for Triglycerides

Neutral Fat Stain

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Procedure for Neutral Fat Stain

emulsified stool + 95% ETOH + Sudan
III

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Value of Steatorrhea in Neutral Fat Stain

≥ 60ORANGE DROPLETS/HPF

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Stain for total fat content (including Fatty acids, soaps/fatty acid salts, and cholesterol)

Split Fat Stain

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Procedure for Split Fat Stain

stool + 36% acetic acid + Sudan III +
Heat

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Value of Steatorrhea in Split Fat Stain

100 droplets that are 6-75 um in
size

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Neutral Fat Stain is NORMAL
Split Fat Stain is INCREASED

MALABSORPTION

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Neutral Fat Stain is INCREASED
Split Fat Stain is NORMAL

MALDIGESTION

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Gold standard quantitative test
for fecal fat content

Van De Kamer Test

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Collection Considerations for Van De Kamer Test:
Requires the collection of ____ specimen.

at least a 3 days

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Collection Considerations for Van De Kamer Test:
The patient must maintain a regulated intake of fat of ____ before and during the collection period

100 g/day

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Collection Considerations for Van De Kamer Test:
The specimen is collected in a _____ container like paint cans

large, pre-weighed

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Collection Considerations for Van De Kamer Test:
The entire fecal collection is ____ and ____ (e.g., using a mechanical
shaker).

weighed and homogenized

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Principle of Van De Kamer Test

Titration or titrimetric method

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Reagents used of Van De Kamer Test

Sodium hydroxide (naoh)

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In the titrimetric method, ____ and ____ are converted to ____ before extraction.

neutral fats and soaps
fatty acids

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Because the titrimetric method is unable to recover medium-chain fatty acids completely, it measures approximately ___ of the total fecal lipid content.

80%

The fat content is reported as grams of fat or the coefficient of fat retention per ____ Reference values based on a ___ are 1 to 6 g per day or a coefficient of fat retention of at least ____

24 hours 100 g/d intake 95%

Normal value if px undergoes standard diet:

1 to 6 g per day

this is useful for children when standard fat diet is used.

Van De Kamer Test

Disadvantage of Van De Kamer Test

time consuming and uses corrosive and flammable solvents

A test that is useful to differentiate malabsorption and maldigestion

D-xylose test

D-Xylose is a ____ that does not need to be ____ but does need to be ____ to be present in the urine

pentose sugar digested absorbed

The xylose absorption test involves the patient’s ingestion of a ____, followed by the collection of a blood sample after ____ urine specimen

dose of xylose 2 hours and a 5-hour

If D-xylose result is low/abnormal, the result indicates a ___

malabsorption

Presence of ≥3 neutrophils/HPF Indicates invasive condition

Fecal Leukocytes

Presence of at least 1 Neutrophil per OIF is significant (Strasinger)

Fecal Leukocytes

Wet preparation of Fecal Leukocytes

Stool + Methylene blue

It is the faster procedure but may be more difficult to interpret

Methylene blue

It is used to differentiate mononuclear cells and PMNs

Methylene blue

A test for fecal WBC that gives a positive result in an invasive bacterial pathogen

Lactoferrin Latex Agglutination

It remains sensitive in refrigerated and frozen specimens

Lactoferrin Latex Agglutination

Lactoferrin Latex Agglutination is positive in diarrhea with WBC: (5)

Salmonella, Shigella, Campylobacter, Yersinia, & entero-invasive E. coli

Lactoferrin Latex Agglutination is negative in diarrhea without WBC: (4)

Staphylococcus aureus and Vibrio spp., viruses, and parasites

Stool stained with either Wright's or Gram stains provides permanent slides for evaluation.

Dried preparation

Occult means “hidden” Screening test for colon cancer

Fecal Occult Blood Test

Significant value of Fecal Occult Blood Test

>2.5ml blood / 150g stool

Sample must be obtained from the ___ portion of the stool to avoid ____ from ____ contamination

center false positive external

Chromogen used for Fecal Occult Blood Test (3)

Benzidine Guaiac Otoluidine

Contrary to most chemical testing, the least sensitive reagent, _____, is preferred for routine testing

Guaiac

Reaction is based on Pseudoperoxidase activity of Hemoglobin

Fecal Occult Blood Test

Aspirin and other NSAIDs will have a result of?

False positive

Aspirin and other NSAIDs should be avoided for

7 days

Red meats, horseradish, melons, raw broccoli, cauliflower, radishes, & turnips will have a result of?

False positive

Red meats, horseradish, melons, raw broccoli, cauliflower, radishes, & turnips turnips should be avoided for

3 days

Reducing agent such as Vitamin C will have a result of?

False positive

Reducing agent such as Vitamin C should be avoided for

3 days

Iron supplements containing vitamin C will have a result of?

False Negative

Iron supplements containing vitamin C will have a result of?

False Negativewill have a result of?

Failure to allow stool samples to soak into the filter paper slide for 3 to 5 minutes before adding developer will have a result of?

False Negative

Applying a thick smear of stool sample on the test card will have a result of?

False Negative

Presence of more than 10 undigested muscle fibers are associated with biliary obstruction, cystic fibrosis, and gastrocolic fistulas

Muscle fibers

Increase excretion of muscle fibers in feces

Creatorrhea

Partially digested fibers

Fibers exhibit striations in only one direction

Patient will undergo in a meat diet

Procedure in Creatorrhea

Procedure of Creatorrhea

Emulsified stool + 10% eosin in alcohol → coverslip and stand for 3 mins then observed under HPF for 5 minutes

Digested fibers

Fibers have no visible striations

Undigested fibers

Fibers have visible striations running both vertically and horizontally

A test for Fetal hemoglobin

APT Test/ Alkali Denaturation Test/ Downey Test

Used to Differentiate fetal blood from maternal blood

APT Test/ Alkali Denaturation Test/ Downey Test

Discovered by Leonard Apt

APT Test/ Alkali Denaturation Test/ Downey Test

Specimen for APT Test/ Alkali Denaturation Test/ Downey Test

infant stool, vomitus, emesis, or gastric aspirate

Reagent used for APT Test/ Alkali Denaturation Test/ Downey Test

1% NaOH

Pink supernatant in APT Test/ Alkali Denaturation Test/ Downey Test:

fetal blood with Hemoglobin F

Yellow-brown supernatant in APT Test/ Alkali Denaturation Test/ Downey Test:

maternal blood with Hb A

Enzymes supplied to the gastrointestinal tract by the pancreas are essential for digesting dietary proteins, carbohydrates, and fats

Fecal Enzymes

Decreased production of these enzymes (pancreatic insufficiency) is associated with disorders such as chronic pancreatitis and cystic fibrosis. Steatorrhea occurs, and undigested food appears in the feces

Fecal Enzymes

Detects trypsin enzyme (absent of trypsin is associated with cystic fibrosis)

X-ray Film test

____ of trypsin has been screened for by exposing x-ray paper to stool _____ in water

Absence emulsified

When trypsin is present in the stool, it digests the ____ on the paper, leaving a clear area

gelatin

Inability to digest the gelatin indicates a deficiency in

trypsin production

More resistant to intestinal degradation and is a more sensitive indicator of less severe cases of pancreatic insufficiency

Chymotrypsin

Chymotrypsin is stable in fecal specimen up to

10 days at room temperature

Measured by spectrophotometry

Chymotrypsin

An enzyme form produced by the pancreas and accounts about 6% of all secreted pancreatic enzyme

Elastase 1

Sensitive and specific test for exocrine pancreatic insufficiency

Elastase 1

The test is specific in differentiating pancreatic from nonpancreatic causes inpatients with steatorrhea

Elastase 1

T/F It is affected by motility disorders or mucosal defects

FALSE NOT AFFECTED

It is measured by ELISA

Elastase 1

The ELISA test uses ____ against human pancreatic elastase-1; therefore, the result is specific for ____ and not affected by pancreatic enzyme replacement therapy

monoclonal antibodies human enzyme

Significant for assessing lactose intolerance

Fecal carbohydrates

Fecal carbohydrates normal pH stool

7-8

Fecal carbohydrates with stool pH and Carbohydrate Disorders:

pH <5.5

a test for reducing sugar (carbohydrate) in Fecal carbohydrates

Clinitest

A result of ___ indicates carbohydrate intolerance

≥0.5 g/dl

LABORATORY TESTS Flashcards

(93 cards)