FOBT

Question 1

Healthy adult - about ___ml of blood per____ of stool from Gl tract daily

Answer 1

2 ml

150 g

Question 2

• >____mlof blood per ____ of stool = pathologically significant

Answer 2

2.5ml of blood/150g

Question 3

• ________= black, tarry stools & blood in stool samples may or may not retain its bright red color.

Answer 3

Excessive GI bleeding

Question 4

• Recommended: Done annually in people older than____

Answer 4

50 yrs old

Question 5

Simple, inexpensive, most frequently performed chemical screening test on stool specimens and noninvasive test (nothing enters the body).

Question 6

• _________ is a term for blood present in the feces that is not visibly apparent. (“occult” or “hidden)

Answer 6

Fecal occult blood

Question 7

• Vital for the detection of blood in the stool that is not visible on gross inspection

Question 8

PRINCIPLE OF FOBT (CHEMICAL METHOD)

______based ready-made reagent test kit - conventional chemical method

Answer 8

Guaiac

Question 9

•_______- principle of chemical tests to detect FOBT

Answer 9

Pseudoperoxidase activity of Hgb and its derivatives

Question 10

PRINCIPLE OF FOBT (CHEMICAL METHOD)

Similar with peroxidase enzymes,____ reacts by catalyzing the transfer of an oxygen atom from the______ (in the developer) to a______ (benzidine, o-toludine, guaiac, aminophenazone)
on the special absorbent paper

Answer 10

Hgb

hydrogen peroxide

chromogen or indicator

Question 11

PRINCIPLE OF FOBT (CHEMICAL METHOD)

•_______- principle of chemical tests to detect FOBT

Answer 11

Pseudoperoxidase activity of Hgb and its derivatives

Question 12

PRINCIPLE OF FOBT (CHEMICAL METHOD)

• These substances vary in their sensitivity.
•_______ - most sensitive
•_______ - least sensitive

• Oxidation of the chromogen is indicated by the production of_____ color.

Answer 12

Benzidine

Guaiac

blue

Question 13

If possible, the px should be placed on a _____________ diet for at least____ days prior to and during the testing period to reduce possibility of positive results due to diet.

Answer 13

red meat-free low-peroxidase

3 days

Question 14

PATIENT PREPARATION FOR TESTING

The patient should not consume: TO AVOID FALSE REACTIONS

Answer 14

a) Rare and lightly cooked meats, especially beef

b) Cauliflower, turnips, broccoli, horseradish, radishes or cantaloupe

c) Iron rich supplements

d) Vitamin C in excess of 250mg per day

e) For 7 days prior to and during the collection period, patients must avoid aspirin and other inflammatory drugs/medications which may cause GI irritation period

f) Excessive amounts of alcoholic drinks

Question 15

PATIENT PREPARATION FOR TESTING

Vitamin C in excess of____ per day (______ reactions have been noted linked dto vitamin C/ ascorbic acid)

Px must discontinue vitamin c supplements___days prior to and during testing period

Answer 15

250mg

Negative

3

Question 15

PATIENT PREPARATION FOR TESTING

For_____ prior to and during the collection period, patients must avoid aspirin and other inflammatory drugs/medications which may cause GI irritation period

Answer 15

7days

Question 16

LABORATORY TEST PROCEDURE - FOBT

NOTE: To increase the chances of detecting intermittent Gl bleeding, it is recommended that stool samples be collected from _______ bowel movements and the _____be made from_______ of each stool sample, especially from______ areas.

Answer 16

3 consecutive

2 smears

2 or more different areas

darkened or discolored

Question 17

LABORATORY TEST PROCEDURE - FOBT

1. Label the______ and______ with the patient’s information.

2.With the provided applicator stick, apply a very thin smear of stool inside the Oval indicating______. Using the same applicator stick, repeat poking the stool in another area or portion and apply another set of thin fecal smear for_____. Discard the applicator stick in the______ trash after use.

Answer 17

stool container as well as the Hema Screen™ card

Roman Numeral I

oval II

biohazardous

Question 18

LABORATORY TEST PROCEDURE - FOBT

3. At the back of the Hema Screen*™ card, open the perforated section, marked_______

a) Apply ______drops of________ to the exposed filter paper.

b) After_______ secs and before ______ read results otherwise the color reaction will fade.

c) Any trace of_____ is positive for occult blood, no indication of blood is negative

Answer 18

1 and 2

2 or more ; Hema Screen™ Developing Solution

30 seconds and before 2 minutes

blue

Question 19

QUALITY CONTROL - FOBT

• Quality control on the Hema Screen™ cards allow the testing for the______ and_____ of the slides and developer.

• Located under the perforated flap on the back of the slide

Answer 19

functionality and stability

Question 20

Note: It is important that______ be performed and developed first prior to testing of the specimen to avoid____ or prejudice of test interpretation

Answer 20

QC

interference

Question 21

QUALITY CONTROL - FOBT

1.Add___ drop of developer directly onto control area (between______
performance standards)

2.Read results within______.
The positive standard contains a _____catalyst. After the addition of the developer, a___ color should appear within____ seconds.

The negative standard should not show a blue color. If the standards do not react as expected, the test results should be disregarded and considered invalid

3. Document results of the performance standards on the patient’s test record.

Answer 21

1 drop; + and -

30 seconds

Hgb derived; blue; 30

Question 22

INTERFERENCES ON TESTING
• In chemical tests, ____________ can cause false positive reactions.

Other substances can interfere with peroxidase activity resulting in false negative results

Answer 22

non-Hgb substances with peroxidase activity

Question 23

Substances than can cause false positive reaction are:

1. Drugs:

Answer 23

Boric acid
bromides
colchicine
iodine

Question 24

Substances than can cause false positive reaction are: 2. Animal Foods:

Answer 24

foods like meats including ***processed meats and liver*** in diet that contain Hgb, myoglobin and certain enzymes

Question 25

Substances than can cause false positive reaction are: 3. Vegetables and fruits ***with peroxidase activity*** (ex: 7) • Substances than can cause false negative reaction are ascorbic acid (Vitamin C) enriched foods and iron supplements that contain Vitamin C

Answer 25

turnips horseradish mushrooms broccoli apples radishes bananas

Question 26

• Other factors affecting test results are:

Answer 26

1. Bleeding hemorrhoids 2. Collection of specimen during menstrual period 3. Hematuria (blood in urine) 4. Some long-distance runners