Positive Coombs Test In Newborns: Causes And Tips To Follow

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The Coombs’ test or antiglobulin test (AGT) is a blood test that helps detect the presence of antibodies against red blood cells (erythrocytes) in the body, which can cause hemolysis. This can lead to hemolytic disease in newborns, also known as erythroblastosis fetalis. A positive coomb’s test in newborns indicates two health problems – anemia and jaundice

However, it doesn’t necessarily mean that the baby has anemia or jaundice but rather that they should be checked for these conditions. Blood samples are taken from the neonate’s umbilical cord during delivery or the veins after birth to conduct this test.

Read on to learn more about different types of coomb tests, their interpretations, and the outcomes for babies with a positive coomb’s test

Types Of Coombs Tests

There are two types of Coombs tests to detect various pathologies(1).

1. Direct Coombs test

Direct Coombs test detects antibodies attached to the red blood cells. After collecting the blood sample, the red blood cells are washed in the laboratory to remove the plasma and unbound antibodies. The washed red blood cells are incubated with Coombs reagent (anti-human globulin) in the next step.

The test is considered positive if the red blood cells agglutinate, that is, appear clumpy or sticky. This indicates that the antibodies or complement proteins are attached to the red blood cells causing their destruction.A baby with a positive direct Coombs test may have autoimmune hemolytic anemia.

2. Indirect Coombs test

Indirect Coombs test detects free antibodies in the blood. These antibodies are not attached to the red blood cells and work against foreign red blood cells. In the laboratory, the blood serum is extracted and incubated with foreign red blood cells and anti-human globulin or Coombs reagent. Indirect Coombs test is considered positive if agglutination is observed.

Indirect Coombs tests help diagnose reactions to blood transfusion. It is also used inprenatal testingto check for Rh compatibility issues in pregnant women. Mothers with Rh-negative blood groups should take anRh immunoglobulin shotduring pregnancy to avoid Rh incompatibility-related complications in their subsequent pregnancies(2).

What Problems Are Seen In Coombs Positive Babies?

The health problems in positive direct and indirect Coombs tests may vary. These may include(3):

1. Autoimmune hemolytic anemia

In this condition, theimmune systemdestroys the red blood cells, resulting in anemia. The lifespan of red blood cells is 120 days, but they are destroyed earlier in this condition. It could lead to anemia since there are inadequate mature cells to compensate for the loss.

Swelling under the skin is one of the common symptoms of hemolytic anemia in babies. Destruction of red blood cells could also cause jaundice.

2. Jaundice

Yellow discoloration of skin and whites of the eyes (sclera) iscalled jaundice. It is caused by excess bilirubin, a byproduct of red blood cell destruction.Babies with indirect or direct Coombs positive test could have jaundice since both attached and free antibodies damage the red blood cells.

Note: Coombs negative babies may also develop jaundice due to immature liver function, breast milk, or erythrocyte disorders.

How To Take Care Of A Coombs Positive Baby?

There is no need for specific treatment in some babies with mild elevation of bilirubin levels. However, babies are closely monitored for changes in bilirubin levels and symptoms. Treatment options may include the following.

• Adequate feedingis recommended sincepoor feedingmay worsen jaundice due to other reasons
• IntravenousⁱX通过一个人的静脉注射药物with the help of a needle.fluids are given if required
• Medications to keep blood pressure normal
• IVIG-intra venus immunoglobulin may be required in some cases to neutralize preformed antibodies
• PhototherapyⁱXThe use of ultraviolet light to treat certain skin conditions, such as psoriasis, eczema, and dermatitis.is given for jaundice
• Severe cases may require a blood transfusion

You may discuss the appropriate treatment plan with a pediatrician.

When Can A Coombs Positive Newborn Go Home?

Coombs positive babies can go home in usual time after birth unless there are complications of high bilirubin levels and anemia. However, you may need to visit a pediatrician within a few days for blood tests to assess the progress.

Sometimes, jaundice and anemia may worsen after going home. You may call the healthcare provider if you notice any of these signs and symptoms(4).

• Increased yellowing of the skin and eye
• Poor feeding
• Breathing difficultiesor fast breathing
• PallorⁱXPale or faded skin color at a specific region or various regions of the body, usually due to trauma or underlying illness.
• Sleepiness

Long-term Complications In Coombs Positive Infants

Most Coombs positive babies do not develop any long-term problems since the maternal antibodies clear within a few weeks after birth. The immune reaction slowly resolves, and the formation of new blood cells helps the infant recover completely in a few weeks(4).

If left untreated, very high bilirubin levels may cause brain damage known as kernicterus and other issues, such ascerebral palsyⁱXA set of disorders affecting a person's ability to move, balance, and maintain proper postures.or deafness. However, in most cases, jaundice is diagnosed and treated before the bilirubin reaches a level high enough to cause complications.

What Happens If The Coombs Test Is Negative?

A negative result (no agglutination present) on direct and indirect Coombs tests means no antibodies or complement proteins are against the red blood cells. It is possible to develop jaundice and hemolytic anemia in babies with negative Coombs tests due to other medical conditions that do not involve antibodies against the red blood cells. Newborns may also develop physiological jaundice and breast milk jaundice during the initial days of life(5).

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