In the US, newborns are tested for congenital disorders of metabolism and a growing list of other conditions by heelstick screening tests. What gets tested by these newborn screening panels is decided by individual states. As a result, there is a substantial variability among state panels. As of April, every state screens for PKU (phenylketonuria), galactosemia and congenital hypothyroidism. Twelve states currently mandate screening for over 40 disorders. These states are able to screen for this high number of disorders with the use of tandem mass spectrometry, which is a technology that analyzes the metabolite composition of the blood spots.

These are all rare disorders: the most common is congenital hypothyroidism (prevalence is about 1 in 3,500), with the rarest being homocystinuria and MSUD (prevalence for is about 1 in 200,000 for each). But intervening early can improve outcomes in many cases, so there is an push to test for more and more conditions.

In terms of drawbacks, the test itself is a simple heelstick. There is additional cost involved in expanded screening, however. Most importantly, as with any screening test, these screens are designed to err on the side of overdiagnosis, so confirmatory tests may be necessary, and "false positives" can certainly cause a lot of stress.

If interested, you can obtain kits for expanded newborn screening for rare inherited disorders through one of these companies:

Pediatrix Screening (866-463-6436)
Baylor University Medical Center (800-422-9567)
Mayo Medical Clinic (800-533-1710)
University of Colorado (303-315-7301)

These services screen for anywhere from 20-50 disorders and the cost ranges from $35 – $89 (plus shipping and handling). Many require the involvement of a physician in the ordering and interpretation. Not all are set up for older/international screening situations. Pediatrix seems to be the only one of these to offer a comprehensive panel that also includes the standard state screens. Unfortunately, since these are newborn screening kits, they are not designed for older infants and toddlers. You'll want to check with the company to see what their age limits are for various tests ...

In the international adoption scenario, provided the child's current legal guardian is OK with testing (a big and usually insurmountable if in most instances, but preadoptive parents in Guatemala have been successful with this), you'll need to be sure that the kit you use also covers the basic newborn screen, and not just tests that are designed to supplement the common state screens. In Korea, they do routinely test for PKU and hypothyroidism. Russia also reportedly tests for these in many regions, but the results are not typically available.

In our clinic we do not routinely send newborn screening tests on international adoptees. The Washington State lab is not set up to run the most important screens on older infants and toddlers. With our initial bloodwork, we do screen for various types of anemia, which should uncover clinically significant hemoglobin disorders, and we also screen for hypothyroidism. If children have symptoms of metabolic illnesses, there are blood and urine tests that we can perform as well.