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Introduction

This antibody study determines the Rh antibody level in an Rh-negative or pregnant woman whose partner is Rh positive. If the Rh-negative woman is carrying an Rh-positive fetus, the antigen from the fetal blood cells causes antibody production in the mother’s serum. The firstborn child usually shows no ill effects; however, with subsequent pregnancies, the mother’s serum antibodies increase and eventually destroy the fetal red blood cells, causing hemolytic disease of the newborn.

Normal Findings

Procedure

  1. Obtain a 10-mL venous blood sample (plasma or serum) from the mother using a yellow-topped (ACD) and clotted blood (not SST) tube. Observe standard precautions.

  2. Label the specimen with the patient’s name, date, and test(s) ordered and place in a biohazard bag for transport to the laboratory.

Clinical Implications

Some institutions have established a critical titer for anti-D below which hemolytic disease of the newborn is considered unlikely. No further investigations are undertaken unless the critical titer level is reached.

Interventions

Pretest Patient Care

  1. Explain test purpose and procedure.

  2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Review test results; report and record findings. Modify the nursing care plan as needed. Counsel the patient regarding abnormal findings; explain the need for possible follow-up testing and treatment.

  2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.