Antibody Titer Case Studies

Please work through these 2 case studies. Ask your site

instructor for additional help if necessary.

CLS 422

Clinical Immunohematology I

Case One A twenty-eight year old woman, Gravida

2 para 1, is seen by her nurse midwife for a routine prenatal visit.

The clinician orders a Type and Screen. The Transfusion Service performs the

screen. The screen is positive with anti-E being identified.

The Transfusion Service performs an anti-E titer, with the following results:

Case One – Initial Titer

Tube 1 2 3 4 5 6 7 8 9 10

11

12

Reaction Strength

4 3 2 2 1 0 0 0 0 0 0 0

Score 12 10

8 8 5 0 0 0 0 0 0 0

Case One – Initial Titer What is the titer of this sample?

16 What is the score?

43

Case One – Initial Titer Is this infant at risk of HDFN?

Yes, anti-E can cause HDFN. What test might the clinician order next?

E antigen typing on the father of the baby. How would that information be useful?

If the father types E negative, the fetus could not have inherited the gene for E, and would also be E negative. Therefore, the maternal anti-E would not destroy the fetal RBCs.

Case One The father of the baby was typed

for E with positive results. The mother had a repeat titer

drawn at her next prenatal visit, one month later.

The Transfusion Service performed a titer on the current sample with the following results:

Case One – Titer Two

Tube 1 2 3 4 5 6 7 8 9 10

11

12

Reaction Strength

4 3 3 2 1 1 0 0 0 0 0 0

Score 12 10

10

8 5 5 0 0 0 0 0 0

Case One – Titer Two What is the titer of this specimen?

32 What is the score?

50

Case One – Titer Two What additional testing must be

done to determine the significance of this titer? Repeat the titer on the initial

specimen, and compare results. The initial sample was titered in

parallel, with the following results:

Case One – Parallel Titer

Tube1 2 3 4 5 6 7 8 9 1

011

12

Reaction Strength

4 3 2 2 1 0 0 0 0 0 0 0

Score 12 10

8 8 5 0 0 0 0 0 0 0

Case One – Parallel Titer What it the titer of this specimen?

16 What is the score?

43 Has there been a significant

change in the titer? NO. There is not a difference of 2

tubes, or a change in score of 10 or more.

Case One The mother returned for a prenatal

visit in 1 month, and had a titer drawn at that time.

The Transfusion Service performed titers on the current specimen, and ran the initial specimen in parallel, with the following results:

Case One – Titer ThreeTube 1 2 3 4 5 6 7 8 9 1

011

12

Reaction Strength

4 4 4 3 3 2 1 0 0 0 0 0

Score 12 12

12

10

10

8 5 0 0 0 0 0Tube 1 2 3 4 5 6 7 8 9 10

11

12

Reaction Strength

4 3 2 2 1 0 0 0 0 0 0 0

Score 12 10

8 8 5 0 0 0 0 0 0 0

Initial Titer run in parallel

Case One – Titer Three What is the titer and score of the third titer?

>E titer is 64, with a score of 69. Has there been a significant change from the

original specimen? Yes, the parallel titer is still 16, with a score of 43.

The new titer has increased by 2 tubes, and the score has changed by more than 10.

How might the clinician follow the pregnancy from now on (other than additional titers)?

Case One Ultrasound

Peak systolic velocity of the middle cerebral artery (MCA PSV)

Amniocentesis Bilirubin levels Fetal lung maturity

PUBS (cordiocentesis)

Case Two A 42 year old woman was seen by

her obstetrician at 26 weeks of gestation during a high risk pregnancy.

An antenatal Rh Immune Globulin evaluation was drawn at that time.

The laboratory performing the RhIG evaluation got a positive antibody screen, with anti-D being identified.

Case Two The physician requested an anti-D

titer be performed. The results were as follows:

Tube 1 2 3 4 5 6 7 8 9 10

11 12

Reaction Strength

1 1 0 0 0 0 0 0 0 0 0 0

Score 5 5 0 0 0 0 0 0 0 0 0 0

Case Two – Titer One What is the titer and score?

Anti-D titer is 2, score 10. What question might the

technologist ask at this point? Has the patient already received Rh

Immune Globulin during this pregnancy?

Anti-D from RhIG rarely titers greater than 4.

Case Two – Titer One A review of the woman’s chart

revealed she had received RhIG following amniocentesis at 18 weeks gestation.

The anti-D detected at 26 weeks was attributed to passive anti-D from RhIG.

The patient received an additional dose of RhIG, and the pregnancy proceeded without complications.

The End

How did you do?If you had problems, review

the titer presentation.