Newborn Testing


Newborn testing is part of the services hospital and birthing centers provide after your baby is born. Depending on what state you live in, there are a number of different newborn tests that your baby will receive.

These screening tests are intended to detect disorders that could result in complications such as early mortality or lifelong disability. Generally, most states only test for selected disorders and not all states do the same screening tests. It is important to be informed about any and all tests that are available for your baby.

Newborn Testing: Types of Tests for Newborns

According to the March of Dimes (MOD), there are tests for over 30 disorders.  However, not all states test for each of these disorders. The March of Dimes believes that states should screen for at least the 30 specific disorders for which effective treatment is available.

The following list of these disorders also includes the number of babies affected if the data is known:

1. 3-Methylcrotonyl-CoA carboxylase deficiency (3MCC)
2. 3-OH 3-CH3 glutaric aciduria (HMG) or 3-hydroxy-3methylglutaryl-CoA lyase deficiency
3. Argininosuccinic acid lyase deficiency (ASAL): 1 in 70,000 babies
4. Beta-ketothiolase deficiency (BKD)
5. Biotinidase deficiency (BIOT): 1 in 75,000
6. Carnitine transporter deficiency (CTD) or carnitine uptake defect (CUD): 1 in every 40,000 babies
7. Citrullinemia (CIT)
8. Congenital adrenal hyperplasia (CAH): 1 in 15,000
9. Congenital hypothyroidism (HYPOTH): 1 in 3,000
10. Cystic fibrosis (CF)
11. Galactosemia (GALT): 1 in 30,000-60,000
12. Glucose-6-phosphate dehydrogenase deficiency (G6PD)
13. Glutaric acidemia type I (GA I)
14. Hb S/Beta-thalassemia (Hb S/Th)
15. Hb S/C disease (Hb S/C)
16. Hearing deficiency: 3-4 in 1,000
17. Homocystinuria (HCY): 1 in every 200,000
18. Isovaleric academia (IVA) 1 in every 230,000
19. Long-chain L-3-OH acyl-CoA dehydrogenase deficiency (LCHAD)
20. Maple syrup urine disease (MSUD): less than 1 in 100,000
21. Medium-chain acyl-CoA dehydrogenase deficiency (MCAD)
22. Methylmalonic acidemia (MMA, Cbl A, B)
23. Methylmalonic acidemia with Homocystinuria (MMA + HCU)
24. Medium-chain acyl-CoA dehydrogenase deficiency (MCAD): 1 in 15,000
25. Phenylketonuria (PKU): 1 in 25,000
26. Propionic acidemia (PROP)
27. Sickle cell anemia (SCA) 1 in 400 African Americans and at lower frequency among Hispanics, Mediterranean, Middle Eastern and South Asian descent
28. Trifunctional protein deficiency (TFP)
29. Tyrosinemia type I (TYR I): 1 in every 100,000 babies
30. Very long-chain acyl-CoA dehydrogenase deficiency (VLCAD)
The most common disorders that are tested for are Phenylketonuria (PKU), Congenital Hypothyroidism, Galactosemia, Maple Syrup Urine Disease, Homocystinuria, Biotinidase, Sickle Cell Disease, Congenital Adrenal Hyperplasia, and Cystic Fibrosis.
The American Academy of Pediatrics recommends that a repeat specimen be taken one to two weeks later from infants whose initial test was taken within the first 24 hours of life.

What newborn tests does my state screen for?

For a list of the newborn tests performed in your state, you can visit the National Newborn and Genetics Resource Center. Newborn screening tests are required by the state. If you do not wish to have these tests performed, you must discuss this with your healthcare provider.

How and when is newborn testing done?

Blood is drawn from the heel of the baby, also known as the heel-stick test before the baby is discharged from the hospital or within a few days of birth. The March of Dimes (MOD) has a timeline for the best time to take the test.

  • The optimal time for taking blood specimen for testing: When the baby is 3-5 days old or between the first 48-96 hours of life.
  • Satisfactory time for taking a blood specimen for testing: When the baby is 2 days old or at least 24 hours since birth.
  • Limited results from blood specimen: When the baby is 1 day old or less than 24 hours since birth.

There are two different testing types:  newborn screening (NBS) and tandem mass spectrometry (MS/MS). The difference between these two tests is that MS/MS tests for many disorders at one time.

In most cases, you will not be notified if the results are negative.  If the result is positive for any of the disorders, you will be notified immediately, and further testing will be performed to confirm any diagnosis. Keep in mind that results can be abnormal if the blood was drawn too early or if the baby is premature. Other factors may contribute to an abnormal result as well.

Should I get additional screening tests for my baby?

There are many reasons why doctors and hospitals do not perform certain tests. This could be due to the availability of the test, cost, insurance, staffing, and if your baby has a low risk of having a disorder. These additional tests are provided through a doctor’s written order, and it is best to discuss them with your doctor.
Possible reasons to consider additional screening tests would be:

  • Previously affected child
  • History of previous infant death with a possible metabolic disorder
  • At-risk ethnic population
  • Family history of the disorder
  • Premature birth

If your doctor thinks that additional testing is not necessary, there are kits you can order from hospitals or laboratories that have these tests available. All you have to do is ask your doctor for an extra blood sample.

Where can I get more information about newborn tests and disorders?

If you would like to get additional testing, you can find out more information from

You can also call Baylor Medical Center at 1-800-4-BAYLOR (1-800-422-9567) or Mayo Medical Laboratories at 1-800-533-1710 where you can request a kit. These kits range anywhere from $25-$77 and test for 30-35 disorders.
If you are interested in learning more about these disorders, you can contact the March of Dimes or National Newborn and Screening Resource Center
Also, if you are planning to have a baby, you can get more information on genetic counseling and testing.