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Anti-D (Rh) Immunoglobulin (Rhogam) Antibody Screening Test

Published: August 9, 2026Updated: August 16, 2026

This test checks for the presence of antibodies against the Rh blood group antigen, which can affect pregnancy or blood transfusions.

Quick summary

["Helps prevent complications from Rh incompatibility during pregnancy or blood procedures."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
51888-6
Short code
Rhogam Gvn BPU
Synonyms
Rhogam Gvn BPU
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Matters for Pregnancy

Rh incompatibility can occur when a mother’s blood type is Rh-negative and her baby is Rh-positive. If antibodies develop, they may cross the placenta and harm the baby’s red blood cells. This test helps identify if antibodies are present to guide further care.

What to Expect During the Test

A small blood sample is drawn from your arm. The sample is tested to detect Rh antibodies in your blood. Results are typically available within 1–3 business days.

When This Test Is Needed

This test is often performed during pregnancy (especially at 28 weeks) or if you’ve had a previous pregnancy with Rh incompatibility, miscarriage, or blood transfusion. It may also be done if you’ve had certain conditions (e.g., ectopic pregnancy) that could trigger antibody formation.

What the Results Mean

A positive result means Rh antibodies are detected. This requires further evaluation (like a confirmatory test) to assess risk to your baby. A negative result means no antibodies were found, but follow-up may still be needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

If antibodies are found, your healthcare provider may recommend additional monitoring, such as amniocentesis or fetal blood sampling, to check for signs of fetal anemia. Rhogam (anti-D immunoglobulin) may also be administered to prevent antibody development in future pregnancies.

Short name

Rh Antibody Screen

Frequently asked questions

Why did my doctor order this test?
Your doctor may have ordered this test if you’re Rh-negative, had a previous pregnancy with Rh-positive baby, or experienced conditions that could increase your risk of developing Rh antibodies.
What does a positive result mean for my baby?
A positive result means Rh antibodies may be affecting your baby’s red blood cells. Your provider will work with you to monitor fetal health and plan interventions if needed.
How often will I need this test during pregnancy?
If your initial test is positive, you may need follow-up tests at specific intervals (e.g., weekly or monthly) to track antibody levels and fetal well-being.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy