PREFINAL LABORATORY L1: HBsAg TEST

Question 1

What type of assay is used in HBsAg test

Answer 1

immunochromatography assay

Question 2

specimens where HBsAg can be detected

Answer 2

human serum, plasma, whole blood

Question 3

name of the principle of HBsAg test

Answer 3

double antibody sandwich assay

Question 4

what substances are dry-immobilized in the test device

Answer 4

colloidal gold conjugated anti-HBsAg antibody complexes

Question 5

what happens to the sample when added to the test kit

Answer 5

migrates by capillary diffusion through the strip re-hydrating the gold complexes

Question 6

according to the principle, what happens to the present HBsAg

Answer 6

react with gold conjugate complexes forming particles

Question 7

the formed particles will continue to migrate until what zone

Answer 7

Test zone

Question 8

the test zone contains what substances

Answer 8

anti-HBsAg antibodies

Question 9

what happens to the formed particles if they reach the test zone

Answer 9

immobilized by anti-HBsAg antibodies, forming a red line

Question 10

what happens to the gold conjugate if there are no HBsAg present

Answer 10

the gold conjugate will continue to migrate alone until the control zone

Question 11

the control zone contains what substances

Answer 11

goat anti-mouse IgG antibody

Question 12

what happens to the gold conjugate when it reaches the control zone

Answer 12

immobilized by goat anti-mouse IgG antibody, forming a red line

Question 13

materials provided by the HBsAg test kit

Answer 13

1) QuickProfile HBsAg test
2) Instructions for use
3) Disposable transfer pipet

Question 14

materials required but not provided

Answer 14

1) whole blood or plasma
2) serum
3) timer or clock

Question 15

acceptable anticoagulants for plasma specimen in HBsAg testing

Answer 15

heparin or EDTA

Question 16

storage temperature of sealed pouches of HBsAg test kit

Answer 16

4-30 C

Question 17

T or F:
test kit must be used immediately after removed from test pouch

Answer 17

T

Question 18

how to dispose HBsAg test specimens

Answer 18

autoclaving at 121C for at least 20 mins or treated with 0.5% sodium hypochlorite 1-2 hours before disposal

Question 19

heat inactivation of spx may cause

Answer 19

hemolysis
protein denaturation

Question 20

if specimens are to be stored, what should be done to avoid hemolysis

Answer 20

remove rbcs

Question 21

what should be done if sample cannot be tested within 24 hours

Answer 21

serum or plasma must be frozen until the test can be performed

Question 22

T or F:
not allowing the sample to reach room temperature will not cause any dicrepancies

Answer 22

F
should be allowed to reach room temperature prior to tetsing

Question 23

what can be added as preservative in HBsAg specimens

Answer 23

sodium azide

Question 24

percentage of sodium azide

Answer 24

up to 0.1%

Question 25

catalog number of HBsAg test strip

Answer 25

71003

Question 26

procedure for HBsAg test strip

Answer 26

1) bring all materials and specimens to room temperature 2) remove the test strip from the sealed foil pouch 3) label the specimen with specimen identity by writing the ID on the top label of the strip 4) place the test strip on a flat horizontal surface 5) use the transfer pipet to draw up the sample 6) hold the transfer pipet in a vertical position over the sample pad and dispense 2 drops of sample onto the sample pad 7) read the result after 20 mins after adding the sample

Question 27

2 drops of sample is equivalent to how many microliters

Answer 27

80-100 uL

Question 28

how many minutes should the result be read

Answer 28

20 minutes after adding the sample

Question 29

catalog number of HBsAg test card

Answer 29

71004

Question 30

procedure for HBsAg test card

Answer 30

1) bring all materials and specimens to room temperature 2) remove the test card from the sealed foil pouch 3) label the specimen with specimen identity by writing the ID area of the cassette 4) place the test card on a flat horizontal surface 5) use the transfer pipet to draw up the sample 6) hold the transfer pipet in a vertical position over the sample well and dispense 2 drops of sample onto the sample well 7) read the result after 20 mins after adding the sample

Question 31

positive samples may show (positive/negative) results before 20 mins

Answer 31

positive

Question 32

results after how many minutes may give inaccurate results

Answer 32

30 minutes

Question 33

interpret: POSITIVE, NEGATIVE or INVALID one colored band appears on C and T

Answer 33

POSITIVE

Question 34

interpret: POSITIVE, NEGATIVE or INVALID faint colored band only appears on T

Answer 34

INVALID

Question 35

interpret: POSITIVE, NEGATIVE or INVALID one band appears on C, faint colored band appears on T

Answer 35

POSITIVE

Question 36

interpret: POSITIVE, NEGATIVE or INVALID one colored band appears on C, none on T

Answer 36

NEGATIVE

Question 37

interpret: POSITIVE, NEGATIVE or INVALID no colored band appears on C and T

Answer 37

INVALID

Question 38

what should be done if test is invalid

Answer 38

repeat test with a new device

Question 39

limitations of HBsAg test kit

Answer 39

1) the test is for in vitro use only 2) negative results do not rule out the possibility of hepatitis b infection or exposure 3) positive results alone cannot be the final diagnosis of infection 4) test is only for testing of individual serum/plasma/whole blood. Do not use for testing other body fluids or pooled blood samples 5) only qualitative detection, does not indicate the quantity of antibodies

Question 40

QuickProfile HBsAg test can detect HBsAg with how many concentration

Answer 40

1.0 ng/mL

Question 41

sensitivity, specificity and accuracy of QuickProfile HBsAg test

Answer 41

99.6%