eMedicine Specialties > Emergency Medicine > Obstetrics & Gynecology

Rh Incompatibility: Differential Diagnoses & Workup

Author: Leon Salem, MD, MS, Associate Attending Physician, Kaiser Permanente, Southern California
Coauthor(s): Karen R Singer, PA-C, Department of Pediatrics, Fountain Valley Medical Center, South Counties Pediatric Critical Care Medical Group, Fountain Valley and Long Beach, California
Contributor Information and Disclosures

Updated: Nov 4, 2009

Differential Diagnoses

Other Problems to Be Considered

ABO incompatibility
Autoimmune hemolytic anemia
Microangiopathic hemolytic anemia
Spherocytosis
Hereditary enzyme deficiencies
Alpha thalassemia
Chronic fetomaternal hemorrhage
Twin-twin transfusion
Erythroblastosis fetalis
Hydrops fetalis

Workup

Laboratory Studies

  • Prenatal emergency care
    • Determination of Rh blood type is required in every pregnant female.
    • In a pregnant woman with Rh-negative blood type, the Rosette screening test often is the first test performed. The Rosette test can detect alloimmunization caused by very small amounts of fetomaternal hemorrhage. When a high clinical suspicion of large fetomaternal hemorrhage is present (>30 mL blood), the Kleihauer-Betke acid elution test often is performed. The Kleihauer-Betke test is a quantitative measurement of fetal red blood cells in maternal blood, and it can be valuable for determining if additional amounts of Rh IgG should be administered. The amount of Rh IgG required for treatment after sensitization is at least 20 mcg/mL of fetal RBCs.
    • Point-of-care blood tests have become available for use in the emergency department and have been shown to have very high sensitivity and specificity in determining Rh status.3
    • Obtaining maternal Rh antibody titers can be helpful for future follow-up care of pregnant females who are known to be Rh negative and may be initiated from the ED. High levels of maternal Rh antibodies suggest that Rh sensitization has occurred, and further studies, such as amniocentesis and/or cordocentesis, may be necessary to evaluate the health of the fetus.
  • Postnatal emergency care
    • Immediately after the birth of any infant with an Rh-negative mother in the ED or prehospital setting, examine blood from the umbilical cord of the infant for ABO blood group and Rh type, measure hematocrit and hemoglobin levels, perform a serum bilirubin analysis, obtain a blood smear, and perform a direct Coombs test.
    • A positive direct Coombs test result confirms the diagnosis of antibody-induced hemolytic anemia, which suggests the presence of ABO or Rh incompatibility.
    • Elevated serum bilirubin measurements, low hematocrit, and elevated reticulocyte count from the neonate can help determine if an early exchange transfusion is necessary.
    • An emergent exchange transfusion, preferably performed in a neonatal intensive care setting with experience in this procedure, is required in infants born with erythroblastosis fetalis, hydrops fetalis, or kernicterus.

Imaging Studies

  • In the ED, ultrasonography of a pregnant female with suspected Rh incompatibility is limited to pelvic ultrasonography.
    • Fetal ascites and soft tissue edema are definite signs of severe involvement.
    • Once hydrops fetalis has developed, the sonographic evidence includes scalp edema, cardiomegaly, hepatomegaly, pleural effusion, and ascites.

Other Tests

  • Perform fetal monitoring in cases of suspected fetal distress. Abnormal fetal heart tones and ultrasonographic evidence of fetal or placental injury are indications of worsening fetal condition requiring emergent delivery, ideally in a center specializing in high-risk obstetric care.

More on Rh Incompatibility

Overview: Rh Incompatibility
Differential Diagnoses & Workup: Rh Incompatibility
Treatment & Medication: Rh Incompatibility
Follow-up: Rh Incompatibility
References
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References

  1. Thorp JM. Utilization of anti-RhD in the emergency department after blunt trauma. Obstet Gynecol Surv. Feb 2008;63(2):112-5. [Medline].

  2. [Guideline] US Preventive Services Task Force. Screening for Rh(D) incompatibility: recommendation statement. Rockville (MD): Agency for Healthcare Research and Quality (AHRQ). 2004;[Full Text].

  3. Herold TJ, Whittaker DS, Glynn T. Determining the accuracy of a rapid point-of-care test for determining Rh(D) phenotype. Acad Emerg Med. May 2005;12(5):474-6. [Medline].

  4. McMahan MJ, Donovan EF. The delivery room resuscitation of the hydropic neonate. Semin Perinatol. Dec 1995;19(6):474-82. [Medline].

  5. Agre P, Smith BL, Hartel-Schenk S. Biochemistry of the erythrocyte Rh polypeptides: a review. Yale J Biol Med. Sep-Oct 1990;63(5):461-7. [Medline].

  6. American College of Obstetricians and Gynecologists. Management of isoimmunization in pregnancy. ACOG Technical Bulletin 148; 1990.

  7. American College of Obstetricians and Gynecologists. Prevention of D isoimmunization. ACOG Technical Bulletin 147; 1990.

  8. Bowman JM. Hemolytic disease (erythroblastosis fetalis). In: Maternal-Fetal Medicine: Principles and Practice. 2nd ed. Philadelphia, Pa: WB Saunders; 1989:613-655.

  9. Copel JA, Gollin YG, Grannum PA. Alloimmune disorders and pregnancy. Semin Perinatol. Jun 1991;15(3):251-6. [Medline].

  10. Daffos F, Capella-Pavlovsky M, Forestier F. Fetal blood sampling via the umbilical cord using a needle guided by ultrasound. Report of 66 cases. Prenat Diagn. Oct 1983;3(4):271-7. [Medline].

  11. Grant J, Hyslop M. Underutilization of Rh prophylaxis in the emergency department: a retrospective survey. Ann Emerg Med. Feb 1992;21(2):181-3. [Medline].

  12. Issitt PD. Race-related red cell alloantibody problems. Br J Biomed Sci. Jun 1994;51(2):158-67. [Medline].

  13. Kleihauer E, Braun H, Betke K. Demonstation von fetalem Haemoglobin in den Erythrozyten eines Blutausstrichs. Klin Wochenschr. 1957;35:637-8.

  14. Mourant AE, Kopec AC, Domaniewska-Sobczak K. The Distribution of the Human Blood Groups and Other Biochemical Polymorphisms. 2nd ed. London, England: Oxford University Press; 1976.

  15. Peterec SM. Management of neonatal Rh disease. Clin Perinatol. Sep 1995;22(3):561-92. [Medline].

  16. Reece EA, Copel JA, Scioscia AL, Grannum PA, DeGennaro N, Hobbins JC. Diagnostic fetal umbilical blood sampling in the management of isoimmunization. Am J Obstet Gynecol. Nov 1988;159(5):1057-62. [Medline].

  17. Selinger M. Immunoprophylaxis for rhesus disease--expensive but worth it?. Br J Obstet Gynaecol. Jun 1991;98(6):509-12. [Medline].

  18. Walker RH. American Association of Blood Banks Technical Manual. 11th ed. Bethesda, Md: AABB; 1993.

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Further Reading

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Keywords

Rh incompatibility, rhesus factor, Rh disease, Rh factor, Rh-negative blood type, Rh-positive blood type, Rh antibodies, maternal Rh antibodies, Rh antigens, Rh sensitization, Rh blood group, Rh immunoglobulin G, Rh IgG, type O blood, O negative blood, Rh-positive fetal blood

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Contributor Information and Disclosures

Author

Leon Salem, MD, MS, Associate Attending Physician, Kaiser Permanente, Southern California
Leon Salem, MD, MS is a member of the following medical societies: American College of Emergency Physicians
Disclosure: Nothing to disclose.

Coauthor(s)

Karen R Singer, PA-C, Department of Pediatrics, Fountain Valley Medical Center, South Counties Pediatric Critical Care Medical Group, Fountain Valley and Long Beach, California
Karen R Singer, PA-C is a member of the following medical societies: American Academy of Physician Assistants
Disclosure: Nothing to disclose.

Medical Editor

Assaad J Sayah, MD, Chief, Department of Emergency Medicine, Cambridge Health Alliance
Assaad J Sayah, MD is a member of the following medical societies: National Association of EMS Physicians
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Mark Zwanger, MD, MBA, Assistant Professor, Department of Emergency Medicine, Thomas Jefferson University
Mark Zwanger, MD, MBA is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and American Medical Association
Disclosure: Medicines Company Consulting fee Consulting; Pfizer Salary Employment

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Pamela L Dyne, MD, Professor of Clinical Medicine/Emergency Medicine, David Geffen School of Medicine at UCLA; Attending Physician, Department of Emergency Medicine, Olive View-UCLA Medical Center
Pamela L Dyne, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

 
 
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