Antibody Screening and Identification

[[p.1]]
Antibody Screening and
Identification
This is an important serological procedure, very much related to the practice of transfusion medicine. A
complicated and delicate investigative procedure in blood group serology for which no substitute has
yet been developed. The operator technologist must be well versed in analytical serology so that he/she
can identify the antibody, or a mixture of antibodies hitherto failed detection by routine procedure in the
serum sample.
The basic principle involves the antigen antibody reaction. The antibody is treated with a panel of
cells, each containing a separate antigen irrespective of incidence and significance and simultaneously
with some cell lacking antigen. The tests are conducted at different phases (R.T. thermal, antiglobulin
phases) in different media, and thereby, enable the antibody to react with the antigen at an optimal
physico-chemical environment needed to elicit the serological reaction that leads to in vitro detection of
antibody, through stages of screening and identification.
Application of tests
1. Multitransfused cases requiring further transfusion.
2. Investigation of haemolytic transfusion reaction.
3. Antinatal serology particularly where rare and clinically significant antibodies are suspected.
4. Autoimmune haemolytic anemia.
5. Donors blood.
6. Research work.
Antibodies may elicit two types ofresponse in vivo after transfusion:
,(a) Immediate: Rapid intravascular haemolysisusually complement mediated,
(b) Anamnestic or secondary response : It is due to secondary exposure to any specific antigen
against whom antibody has' been inducted during the course of primary response.
Primary response is usually produced due to less complement binding antibody of IgG2 or IgG4
subclass and they react very poorly with complement and as such red cells coated with such antibodies
are phagocytosed and removed or many cause very mild reaction.
140

[[p.2]]
Antibody Screening and Identification
141
It is also expected that due to polymorphism of blood group antigen some incompatibility between
donor and recipient may occur.
Combination of the above described two or anyone singly may lead to some antibody production in
a course of five to seven days. These antibodies are of low concentration and the time when it reaches a
significant level, transfused red cells goes out of circulation and the antibody gets diluted though, does
not disappear completely from circulation. And in case of a second transfusion, if the antibodies are
exposed to second dose of specific 'antigen, it replies by a brisk secondary response and large amount of
antibodies may be produced within a very 'short period. This type of secondary response that produces
adverse symptoms may suddenly appear after transfusion is completed and at a time when the patient is
relaxing.
The importance of antibody screening is thus .well explained from the aforementioned statement. A
first hand knowledge-is thus essential regarding clinically significant antibodies so that during screening
proper- attention may be paid to these group of antibodies.
A mismatched transfusion is invariably followed by in vivo transfusion .reaction which could be
overt or,non-overt (diminished cell survival). Antibodies responsible for such reaction in any of the form
described are called clinically significant antibody and are graded according to the severity of reaction
exhibited. Attention are to be paid speciallyto these group antibodies, as because they. can induce
haemolytic transfusion reaction in any Conn described above and these antibodies are thus potentially
dangerous for safe practice of transfusion. In Table 7.1, a list of antibody, commonly encountered in
screening stage is briefly described alongwith some of their reaction pattern so that a guess can be made
at the screening stage itself before proceeding to identification stage. The Table 7.1 is followed by
procedure for screening and identification stage.
· Unexpected antibodies has to be screened and detected during pretransfusion testing to ensure a
safe blood transfusion. First stageis cross-matching stage when the technologist may suspect the presence
ofan antibody. Ifso, he can proceed for screening of antibody in the serum and then identify the particular
antibody so that he can select the appropriate blood lacking the antigens for further processing that is
cross-matching (dealt in chapter of Blood transfusion) and issue compatible blood.
Application of screening tests are already stated. For conducting a screening test, we require the
screening cells. All the screening cells are ofgroup '0'. These cells can be prepared in the laboratory or
commercially acquired.
Preparation of panel cells
(i) Collect atleast ten anticoagulated sa,ples of '0' group donors, Fresh samples preferred from
genotypes RtR1, R1wR1, ~~
Ror, rr, rr,
r'~r,
IT, IT of any five positive and negative donors of
different Cde combination.
(ii) Now take one volume of antisera viz. anti-Rh, say -C, -C, -D, -E, -e; anti-MNSs say -M, -N,
-S, -s; anti-P; anti-Kells say -K, -k-;.anti-Lewis say -Le", -Leb; anti ...Kidd say -JKa, JKb; anti
Lutheran -Lua, -Lub•
(iii) Prepare 2~.
cell suspension in saline of ten individual cells as described in step (i).
(iv) Serially arrange the tubes with antisera in ten rows.
(v) Add two volumes of 2% cell suspension in saline of any cde combination prepared, to all the
tubes serially arranged with one volume of antisera in them. Arrangement of tubes has been

[[p.3]]
142
Blood Banking and Transfusion
Table 7.1. Commonly encountered antibodies .'
Clinical
Reactivity
Typesof
Grade
significance
antibody
HDN, HT*
Mostlyin salineat RTthenat 4°C sometimesin enzyme
10M
ABO
.Highly
at RTand rarelyat albuminandAHG at 37°C
significant
HDN,HT
Mostlyat AHG at 37°C thenin enzymeand albumin
IgG
D
sometimes at RTrarely at 4°C
HDN,HT
Mostlyat AHG at 37°C sometimes in albuminat RT
IgG
Kell
rarelyin salineat RT
HT,rarely cause
MostlyatAHG at 37°C and 4"C are destroyedby enzyme,
IgG
Duffy
HDN
sometimes in saline,albumin,enzymeat RT
HDN, HT cause
Mostlyin AHG at 37°C, then in enzymeand albumin
Ig9
Kidd
Significant
secondary
sometimes in salineat RT, rarely at 4°C
IgG
response
Problem in cross
Mostlyin AHG at 37°C, sometimes in albuminand saline
IgG
C
match rarelyHDN
at RTrarelyat 4°C, destroyedby enzyme
Problem in cross
Mostlyat AHG at 37°C,enzymeand albuminsometimes
IgG
E
match rarely»DN
in salineat RTrarelyat 4°C
Problem in cross
Mostlyin AHG at 37°C sometimes in albuminand saline
IgG
Ssu
match HT,HDN
at RTrarelyat 4°C, destroyedby enzyme
HDN, cross match
Mostlyat salineat 4OCt then in enzyme,sometimesat
IgM
Lewis
Sometimes
albumin in RT, rarely at 37°Cin AHG
significant
Cross matching
Mostlyin salineat RTor 4°C sometimes in AHG at 37°C
IgM
MN
and HDN
destroyed by enzyme
RareHDN
Mostlyin AHGat 37°Cthen in enzymeand albumin,
IgG
e&c
MildHT
sometime in salineat RI, rarelyat 4°C
RareHDN
Lu"mostlyin salineat 4°C, Lub mostlyin ABO at 37°C,
IgM
Lu
HTmild
rare in saline
Cross match
Mostlyin salineat 4°C, sometimes in papainand albumin
IgM
PI
and HDN
at RT, rare in AHOand enzyme
AIHA, i in cord, I
Mostlyin salineat 4°C, sometimes in albuminand enzyme
IgM
Ii
in adult I alteredin
at RT, in autocoldsaline,rare in AHG
diseases like
leukaemia and
haematological
disorder
CHAD red cells
Mostlyin AHG at 37°Cnonreacting with enzymetreated
Ch
Rarely
carry more c4d and red cell
and
significant
thus reacts with
Rg
anti-ch and anti-Rg
Mild HT
Mostlyin salineat RT, sometimes in enzymeand rare in
IgM
Sda:
AHGat 37°C
AIHA.(?) sex chro- Mostlyin AHG at 37°C,inactivated in enzymeprotease
IgG
Xg
Mance aneuploidy
HDNmildHT
Mostly.in AHGat 37°C
IgG
Diego
HDN,AIHA
Mostlyin AHGat 37°Csometimes in salineat RT
IgG
Wr
Rarely HT
MostlyinAHG at 37°C
IgG
yt
HDN : Haemolytic diseaseof newborn; CHAD: Cold haemagglutinin disease;
AIHA : Autoimmune haemolytic anemia; HT : Haemolytic transfusion reaction.
~
--_._.~

[[p.4]]
Antibody Screening and Identification
143
described in step (ii). For convenience first few rows (4 or 5) may beof Rh positivecells and
next few rows (6 or 5) may be of Rh negativecells.
(vi) Incubate all the tubes at 37°C,forone hour.
(vii) Wash all the tubes with its content for at least thrice with normal saline after the incubation
periodis over.
(viii) After final wash' decant supernatant as completely as possible and to the cell button; add two
dropsof AHG and incubatefor five minutesat RT.
(ix) If no agglutination is observed, a low speedcentrifugation is done for one minute. Observefor
agglutination, presence indicates the presence of particular antigen cells are thus ready for
screening purpose.
.Table ::7~2~"
S~owlng:,
arr~~geme~t,':
or:',a', pa~et
'or,,:'red:cells',for ',$ct.e~~~~g,
No. Donor
Gena-
RH
PO Lewis
Lutheran
Kell
Dutty
Kidd
MNSS
group
type-
-
--
Rh
D
C
E
e
e
,Pt
Lea ' Leb Lu"
Lu~
K
k
Fya
Fyb JKI JKb M
N
S S
1
0
R]R]
+
+
- -
+
+
-
+
-
+
+
+
+
-
+
-
+ -
+ '-
2
0
~R2
+
-
+
+ -
+
+
-
-
+
-
+
-
+
-
+
-
+
-
+
Screeningtests(Table 7.2) for antibodies are doneby puttingthecell and serumin appropriateratio
indifferentmediaatdifferent temperature sothatthemaximum possible detection canbedone.Commonly
followed technique are : (a) Saline at RT, (b) Albumin at 37°C, (c) Enzymeat 37°C, (d) IAT(Indirect
antiglobulin test).
(a) Saline test :
(i) Twotubes all glass roundbottomed 10 x 75 mm.
(ii) Twodropsof recipient/patients serumto each of two tubes.
(iii) Screening cells 2% suspension one drop to each tube.
(iv) Shakemanually and thorough mixingis done,
(v) Incubate at RTfor one hour.
(vi) Observe for agglutination if any afterdislodging the cell button.Nakedeye examination is
done. For negative reactionconfmn under microscope.
(vii) Haemolysis, if presentis co~sidered
positivereaction.
(b) Albumin test : Additiontest beingeasier is commonly used.
In the thirdstepas described abovein salinetest add two dropsof 22%BovineSerumAlbumin
(BSA) and continuethe other steps i.e. incubate ~t 37°C for 15 to 20 minutes, centrifugeand
resultsrecorded. Since the test enhances the reactionof incomplete antibodyespeciallyIgG, it
is commonly employed for Rh antibody screening.
(c) Enzyme test: Papaincysteinis commonly usedbecausein this procedure, one stagetechnique
is used.Onedropof Papain-cystein is addedin the third stepof salinetest. Incubateat 37°C for
30 to 45 minutes. .Mild centrifuge and record the result haemolysis and agglutination both
c~nsidered
positive. Negativetest is confirmed under microscope.
Autocontrol to be ron along with test. EnzymedestroysM, N, S, Fya, Fyb.

[[p.5]]
144
Blood Banking arid Transfusion
(d) Indirect antiglobulin test: Refer the chapter of antiglobulin. In screening test, 2 drops of
recipients serum with one drop of screening cell to each of two tube incubation at 37°C for 60
minutes, other steps are same as antiglobulin test validity, of the test should be checked.
Collection of sample for screening
Aclotted sample is always recommended because anticoagulant in plasma is anticomplementary. Sample
must be examined before it is received and it should not contain any contaminant neither it is haemolysed.
In case of infants below three months, the infants sample has to be accompanied by mother's sample for
antibody screening in mother's serum. Infusion line with dextran flowing is to be avoided for collection
of sample.
Sample should be preserved for at least seven days at a temperature ranging between 2° to goC.
Antibody Identification
After screening is done next we proceed to identification ofanantibody which is most difficult procedure
and requires a thorough knowledge of analytical serology related to blood group serology. Some
preliminaries deemed essential will be helpful in identification and they are as follows ":
1. Detailed history of patient : .
(a) case history
(b) past history
(c) personal history
(d) history of any drug therapy.
2. Probable diagnosis and treatment being followed.
3. In case of female:
(a) menstrual history
(b) antinatal history
(c) Rh immunoglobulin therapy
(d) history of stillbirth etc.
4. Any previous laboratory investigation with result viz. :
(a) grouping of blood
(b) subgrouping
(c) Rh grouping etc., if it is a sample from incompatible transfusion or iIDN result of DCT
test.
Transfusionist may rely on the test result obtained from the patient or redo the test himself which
will be confirmatory to above finding and is definitely .abetter proposition.
Panel of cells to be used for identification has already been described and it consists of eight to ten
'0' group blood with 50% being Rh positive and 50% being Rh negative and is collected from different
donor and are tested for maximum antigen of different clinically significant blood group system viz.,
Rh, Kell, Duffy, Kidd, MNSS, Lewis, Lutheran, this is further supplemented by autoeontrol, two groups
of cord cells 0 Rh 'D' positive and ORH 'D'· negative.

[[p.6]]
,Antibody Screening and Identification
145
Blood sample should be freshly collected, should not contain any contaminant. To avoid contaminant
in sample, use disposable needle and syringe and sterile dry all glass vial. The clotted sample is
recommended. To detect the antibody following method for testing the serum is recommended. The
result of test serum is then.compiled. The result obtained from test with panel cell is compiled. Both has
to be compared to detect the antibody.
Methods for testing unknown serum
1. Saline method :
(a) Saline at 4°C
(b) Immediate spin
(c) Saline at RT for 60 minutes
(d) Saline at 37°C with AHG
2. Albumin:
(a) Immediate spin
(b) 37°C for 30 min.
(c) 37°C with AHa, addition technique with 22% BSA.
3. Enzyme
fa) 37°C for 30 minutes
(b) 37°C with anti-human globulin (one stage technique with papain cystein).
The test serum is treated by all the procedure described as above. Stepwise as described in screening
of cells for the three methods and antihuman globulin test are to be followed with alterations such as
setting of temperature and incubation period in respect of each method mentioned above.
Purpose for testing the serum in different methods in different media at 'different temperature is
described below mentioning. the salient points only.
Saline
At RT, it mostly identifies the IGM antibody, anti-M, anti-Lea, anti-Leb, anti-N, anti-H, anti-Lu" at 12to
20°C. At 4°C, it detects cold agglutin namely PI.
Enzyme
Mostly detects IgG complement binding antibody warm reacting namely Rh, Lewis, Kidd antibody
enzyme destroys M, N, S, Fya, Fyb. It can detect both types of antibody (i) alloantibody, (ii) auto-
antibody. It can also detect A, B antibody and PP1 PK from IGM type of'antibody.
Albumin
Amongst the 10M type, it can detect PPIPK at RT and sometimes exhibit reaction with Lu, M, Nand P
at RT. At 37°C, it reacts with Rh antibody in saline andAHO and sometimes reacts with -S, -s, -K, -JK.
AHG
It can detect almost all IgO complementbinding antibodies namely kell, Kidd, S, s, then it also detects
D, C, E, e, c. Then 10M antibodies Lu" and Lu b, Lu" reacts more strongly in saline then AHG reverse is
the case of Lub and PP.·PK.

[[p.7]]
146
Blood Banking and Transfusion
~rocedure
At first an arrangement of panel cells is to be made which can be prepared in laboratory '(described
earlier) to procured from commercial source. This cell panel is prepared in such a way that it represents
maximum antigen. In routine laboratory test, the cell panel consists of maximum antigen that can detect
clinically significant antibodies. Panel consists ofcell from ten individual donors. A panel mostly consists
of D, C, E, c, e, CW, M, N, 5, s, PI' LUI,LUb, lei, Leb, K, K, Kp8 , JSI, JSb; Fyb, JKa, JKb, this typical
panel of cell please observe that out of ten different donors 'D' antigen is present in four and negative in
six and likewise in C, it is present in five and absent in five.
Table,7.,3. Pattem, or c~lIpane
Donor D C E c
e
CW M N S
s
P lei Leb Lul·Lub K
K
Kpi
JSI
Jk8
Jkb
Fya Fyb
•
f) r1
1
0 +00+
0
+ + 0 0
+
0
0
0
+
0
+
0
0
+
+
0'
0
R}R}
2
+ +00+
+ o + o +
+
+
0
0
+
0
+
0
0
+
+
+
0
R.R.
3
+ +00+
0 o + + +
+
0
+
0
+
+
+
+
0
0
+
+
+
~~
4
+
0 + + 0
0
+ + + +
+
0
+
+
+
0
+
0
0
+
+
+
+
rr
5
0 00 + +
0
+ .+ o +
+
0
+
0
+
0
+
0
0
+
0
0
0
rr
6
0 00 + +
0
+ + + 0+
0
+
'0
0
+
0
+
+
0
0
+
+
+
T" r"
7
0 00 + +
0
+ + + 0
+
0
+
0
+
+
+
0
+
0
+
0
+
R"R" 8
0 0+ + 0
0
+ 0 0
+
+
0
+
0
+
0
+
0
0
0
+
0
+
.
~Rl
9
+
+ + 0 +
0
+ 0-0 +
+
0
+
0
+
0
+
0
0
+
+
+
0
ryry
10
0
+ + 0 0
0
+ + o +
0
0
+
0
+
0
+
0
0
+
+
.+
0
Patient + +00+
0
0++ +
+
+
0
0
+
0
+
0
0
0
+
0,
+
0+
Cord 1
Orr
Cord 2
After setting panel cells we then proceed to the reaction of test serum in saline, enzyme and albumin
as described above. If carefully observed, a trained eye can have an educated guess as to what type of
antibody is present in the test serum. The reactive pattern shown by a test sera corresponds exactly to the
distribution of antigen among the panel of cells. Let us take for example, the test sera shows reaction in
saline at 4°C as follows with donor cells, auto and cord cells.
Auto
CordI
C6rd 2
T8st~:s8ra
'reaction '8 .4OC,ln :'88llne
rr"
R1R1
~IRl
~R2
rr
rr
rr
R"r"
~Rl
r/y
+
+
+
+
+
0
+
+'
+
0
o
o
o
Now match the resultor the reactive pattern shown by test serum with distribution of antigen in
panel of cells in Table 7.3 and you find that it matches PI and anti-PI is a saline reacting cold agglutinin
in most of the cases as such antibody present in the serum can be guessed as anti-PI of course, it is
subject to further confirmation by other tests such as absorption and elution (refer to Chapter 14) and
particularly in this case.

[[p.8]]
Antibody Screening and Identification
'47
This is a typical case with one antibody but there could be a mixture of antibody present in that case,
it is very difficult to trace out or guess the antibodies present. But antigen is required to be worked out
and for which we must have a thorough knowledge of different reactions exhibited. This is usually done
by matching and exclusion process. Following is an example (Table 7.4).
Tabl.e .7.4' Reactive pattern eXhib~ted··hy.
test.serum and..It matching· .
.
.
.
Donor
Saline'at
tAT
Albumin
Enzyme
Matching with panel
Sl. No.
at 37°C
saline
37
IAT
37
IAT
37
IAT
c
FYA
1
0
0
0
0
0
O·
0
0
2
W
+
W
+
0
0
0
+
3
W
+
W
+
O.
0
0
+
4
++
+
++
+
W
+
+
+
.5
+
+
+
+
W
+
+
0
6
++
+
++
+
W
+
'+
+
7
+
+
+
+
W
+
+
0
.8
+
+
+
+
W
+
+
0
9
W
+
W
+
0
0
0
+
10
W
+
W
+
0
0
0
+
Auto
0
0
0
0
0
0
0
0
Cord 1
0
0
0
0
0
0
O·
0
.Cord2
0
0
0
0
0
0
0
0
Interpretation of result
Observation
1. Presence ofantibodies that is reacting at saline 37° and albumin 37°, IATsalinc and IAT albumin.
2. In saline 37°C and Albumin 37°C showing reaction at some places, agglutination + and ++.
3. In Enzyme, it shows typically one reacting both at 37°C and lAT.
lnference
(a) The antibodies belong to incomplete type.
(b) The antibodies are two in number.
(c) Both reacting at saline and albumin at 37°C and lAT.
(d) Only one is probably reacting with enzyme the other one might have been inactivated by enzyme.
Now if match the reactive pattern in enzyme 37°C and I.A.T., we will find matching in c antigen in
test panel and if this is subtracted from total reaction exhibited media by serum, we.may get a pattern
almost identical with Fya in panel of cells. It is further confirmed by the fact that -Fya though an IgG

[[p.9]]
148,
BlOOd Banking and Transfusion
like -c, anti-Fya is inactivated destroyed in enzyme media. So in enzyme media test, serum did not
reflect the presence of anti-Fya.
Result
Probable antibodies present are -c, and -Fy" no auto antibody, no i antigen could bedetected, result has
to be further confirmed by absorption elution etc. before arriving at a final conclusion.
By the method of identification described above where test serum shows clear positive and negative
reaction, we have an idea regarding specificity of antibody but to have conclusive evidence we can
apply a simple statistical method. Fisher's Exact method (2 x 2 table) while analysing the result.
Table .7.5~
:'Fishers exact test
Known cell
,Probability is thus
Unknown serum +ve
a
b
a+b
a + b! c + d! b + d! a + c
.Unknown serum -ve
c
d
c+d
N! a! b! c! d
(a + c) + (b + d) n
This formulae is only applicable when one of the variable is 0 and N is not more than 20*.
The above is applicable to clearcut reaction but when it is not a clear cut reaction, it could be due to
mixture of antibodies listed or unlisted such indeterminate .results always create problem in antibody
detection. In such cases, it is always better to use more sensitive technique with wider panel of cells.
Sensitive technique may include liss; use of'selective enzymes, e.g. xg inactivated by enzyme proteases
in Rh detection panel f, v, CW etc. may be included, search for cold agglutinin I and HI has to be done
and rare antibody like U, Vel, m etc. may be made. In India para Bombay phenotype is most relevant.
Proper research may even lead to discovery of new system..
There may arise condition when.serum shows positivity with all standard cell but negative with own
cell, this could be due to :
(a) anyone of the high frequency antigen.
(b) a group of antibody which reacts preferentially with '0' group cells.
(c) mixture of antib~dy
Another condition may often be seen where unknown serum gives positive reaction with all cells
including own when one has to consider :
1. optimum reaction at saline, RT and AIHA has to be excluded.
2. optimum reaction at IAT at 37°C.
3. could be due to pseudo-agglutination.
Negative reaction throughout could be due to anomalous ABO and Rh grouping, not investigated
properly and straight way committed for antibody screening and identification, against a panel of group
'0' cells investigation of such type of reactions as described above, is academic in nature and research
* Consult table 15.9 and 15.10 -
Mathematical consideration)

[[p.10]]
·Antibody .Screening and Identification
149
oriented which is beyond the scope of this book. Interested .readers are referred to consult "Blood group
serology" by Boorman, Dodd a..id Lincoln, 6th edition, 1988, Churchill Livingstone.
GEL TECHNOLOGY IATnCT
Recent advancementin IAT/ICTprocedure for antibody screening and identification is the Gel technology
described below. A card, fixed with six microtubules each of three contains polyspecific AHG and
monoclonal c3dwithin gel matrix are provided readymade by manufactureralong with additionalmaterials :
(a) Diluent: A modified LISS for red cell suspension
(b) Test cell reagents : Cell panel.
Procedure require following essentials to be observed :
(i) Identify the card with patients or donor's name and registration number.
(ii) Card dried up, damaged, seal broken or air bubble in microtubules to be avoided.
(iiiO Dispenser, pipettor, tips, all glass tube for suspension centrifuge for cards of 6 or its multiples
viz. 12, 24 etc.
(iv) Sample may be collected in EDTA, citrate or in plain vial.
(v) Red cell suspension is prepared by putting 10 ulpacked red cell in 1 ml of diluent containing
LISS, then mix gently 0.8% red cell suspension is made.
(vi) Plasma or serum.
(vii) Before use card is to be allowed to attain room temperature.
The test for IATIICT respectively for screening and identificationof antibody is described below:
A. For screening of antibody :
(i) Card, sample and test cell reagents (ready to use) are allowed to attain room temperature.
(ii) Identify appropriate microtubules against patient or donor to be screened.
(iii) Foil to be removed as per requirement.
(iv) 50 III each test cell reagent (appropriate microtubules marked for corresponding cells).
(v) Add 25 ul of patient's or donor serum to each of above microtubules.
(vi) Autocontrol 50 JlI of sampler's own red cell suspension in another microtubule.
(vii) Incubate the card at 37°C for 15 minutes.
(viii) Centrifuge the card at card centrifuge for another 10 minutes.
(ix) Results to be interpreted and recorded.
Interpretation :
Positive : Presence of irregular antibody verify the number of test cell that corresponds with
antigen table. Follow up with further test and identify antibody.
All positive including autocontrol could be due to non-specific infection.
Negative reaction indicates that no irregular antibody is/are present.
B. For identification ofantibody:
(i) Take two cards of 6 and more than 1 to 12 and identify with name of patient or donor -
remove the foil of aluminium.

[[p.11]]
150
Blood Banking and Transfusion
(ii) Allow the panel of cells and card to attain room temperature.
(iii) 50 JlI of test cells in tubes marked 1 to 11. 12th is for autocontrol.
(iv) 50 fll of sampler's own red cell suspension in tbe 12 only.
(v) 25 fll patient's or donor's plasma of serum to all 12 microtubules.
(vi) Incubate at 37°C for' 15 minutes.
(vii) Centrifuge in card, centrifuge for ten minutes.
(viii) Read and record.
Interpretation ofresult: Positive indicates presence of irregular antibody verify with corresponding
number in the antigen table. Autocontrol must be negative.
All positive including autocontrol is due to non-specific reaction.
All positive with negative autocontrol or out of all positive, some showing stronger reaction with
negative autocontrol may indicate the presence of alloantibody.
Positive : Presence of irregular antibody.
.Books recommended for further reading
1. Blood GroupSerology, Boorman, Dodd and Lincoln, 6th edition, 1988, Churchill Livingstone.
2. BloodGroupinMan, Raceand Sanger, Fifthedition, secondreprint,1968,Blackwell Scientific Publication.
3. BloodTransfusion inClinicalMedicine, P.L. Mollison, seventhedition, 1983, BlackwellScientific Publication.
4. Transfusion Medicine Technical Manual, R.K.SaranandR.N. Makroo, DGHS(Ministry ofHealth& Family
Welfare), 1991, Sponsoredby WHO.