Laboratory Activity 4 – Specimen Collection and Processing

Question 1

Basic to laboratory testing are the

Answer 1

proper identification, collection, and processing of the specimen.

Question 2

is the general specimen collected, which is then processed to serum

Answer 2

blood

Question 3

may also be used for serologic testing

Answer 3

other biologic fluids

Question 4

is often prepared in the serology laboratory and used as an indicator reagent to agglutination reaction or complement fixation

Answer 4

red cell suspension

Question 5

T or F

Various factors affect the accuracy of testing and reliability of results; it is, therefore, essential to avoid these sources of errors during the collection and processing.

Answer 5

TRUW

Question 6

is crucial in ensuring production of quality test results

Answer 6

knowing the nature of the specimen and reagent

Question 7

most frequently encountered specimen in the immunology-serology laboratory is

Answer 7

serum

Question 8

the scientific study or diagnostic examination of blood serum

Answer 8

serology

Question 9

Blood specimens are collected through

Answer 9

venipuncture procedures (syringe or evacuated tube method)

Question 10

can be used in immunology-serology tests

Answer 10

Glass red-top tubes (plain) or plastic red-top (with clot activator)

Question 11

specimen of choice for all antibody screening methods

Answer 11

serum derived from clotted whole blood

Question 12

are unacceptable because the additives can interfere with the serum screen assay

Answer 12

Specimen tubes with clot activators and serum separators

Question 13

Glass red-top tubes usually take about [?] for plastic red-top tubes to completely clot.

Answer 13

60 minutes and 30 minutes

Question 14

Care must be taken to avoid hemolysis, since this may produce a false-positive test result.

Answer 14

SERUM

Question 15

Allow [?] before centrifugation, and serum should be promptly separated into another tube without transferring any cellular elements.

Answer 15

complete clotting

Question 16

However, if the serum is contaminated with erythrocytes, it should be

Answer 16

re-centrifuged

Question 17

Serum samples that are allowed to sit [?] are likely to retain cellular elements and other contaminants that will have an impact on future analysis.

Answer 17

less than 30 minutes

Question 18

Samples that sit longer than [?] are likely to experience lysis of cells in the lot releasing cellular components not usually found in serum samples.

Answer 18

60 minutes

Question 19

If testing cannot be performed immediately, serum may be stored between [?].

Answer 19

2°C and 8°C for up to 72 hours

Question 20

If there is any additional delay in testing, the serum should be frozen at

Answer 20

–20°C or below

Question 21

Always observe the [?] of specimens.

Answer 21

complete and proper labeling

Question 22

is the process that destroys complement activity.

Answer 22

Inactivation

Question 23

is known to interfere with the reactions of certain syphilis tests

Answer 23

Complement

Question 24

can agglutinate latex particles and cause a false-positive reaction in latex passive agglutination assays

Answer 24

Complement

Question 24

may also cause lysis of the indicator cells in hemagglutination assays.

Answer 24

Complement

Question 25

is intended to inactivate serum complement.

Answer 25

Heating serum

Question 26

This is done by placing serum samples (in a properly labeled test tube) in a water bath set at 56°C for 30 minutes.

Answer 26

Heating serum

Question 27

When more than 4 hours have elapsed since inactivation, a specimen can be re-inactivated by heating to

Answer 27

56°C for 10 minutes

Question 28

often utilized an indicator reagent to selected agglutination reactions or complement fixation tests

Answer 28

Red cell suspension (RCS)

Question 29

Red cell suspensions prepared from clotted samples should be [?], and suspensions prepared from freshly anticoagulated samples should be [?], both of which could lead to false results

Answer 29

free of clots
free of fibrin

Question 30

Red blood cells suspended in a liquid medium such as normal saline solution (NSS) should be between [?] for standard tube agglutination tests, with an ideal strength of about [?]

Answer 30

2% and 5%
3%

Question 31

Procedure in the Preparation of 2-5% Red Cell Suspension
a. Transfer carefully [?] of the whole blood or packed red blood cells from plasma preparation into a graduated centrifuge tube
b. Washing phase:
(1) Add normal saline solution (NSS) up to the [?] mark of the centrifuge tube
(2) Cover the mouth of centrifuge tube using Parafilm, then mix by gentle inversion, [?]
(3) Centrifuge the tube for [?], discard the supernatant fluid using a Pasteur pipette, leaving the red blood cells.
(4) Repeat steps [?]two or three more times until the supernatant is clear.
c. After the final washing, note the volume of the washed packed red blood cells (WPRBC) before the supernatant is completely removed by [?].
d. Compute for the [?] and the [?] to be added to the washed red blood cells to come up with the desired concentration (in %) of the RCS using the derivation and formula

Answer 31

a. <1.0 mL
b.
1. 10 mL
2. 2-3 times
3. 5-10 minutes at 2,500 rpm
4. 1 ® 2 ® 3
c. aspiration
d.
- total volume (TV) of the RCS preparation
- volume of the diluent (NSS)

Question 32

e. From the total volume computed (TV), determine the volume of the diluent to be added to the washed packed RBC (WPRBC) by using the following derivation and formula:

Question 33

f. Add the appropriate volume of [?] to the [?] to prepare the desired concentration (in %) of the RCS

Answer 33

NSS
WPRBC

Question 34

g. The suspension is mixed thoroughly to produce a [?]. Check for the presence of clots in the suspension.

Answer 34

homogenous solution

Question 35

h. Label the RCS according to the

Answer 35

concentration, blood (antigen) type, and preparation date