PEDIATRICS Vol. 108 No. 3 September 2001, pp. 821

The Importance of Newborn Screening

To the Editor.

The commentary by Howse and Katz¹ commendably calls for equity in access to newborn screening tests and uniform quality of those tests. However, they miss the mark in downplaying economic and cost-benefit considerations and in stating that "a test (even for a rare disease)as long [as] its early discovery makes a difference to the childmust be conducted for every newborn." Such an uncritical approach would be bad public policy and potentially bad for children and their families. Because someone has to pay for the test and for necessary follow-up, economic issues must be considered in arriving at policy decisions.

In 1995, the most recent year for which data are available, 40 states charged a fee (ranging from $10.50-$59.00) for newborn testing.² With respect to follow-up, the recent article by Kwon and Farrell³ demonstrates that, even with a highly sensitive (100%) and specific (99.7%) test, there are 30 false-positives for each case of phenylketonuria detected. Sensitivity and specificity are inherent characteristics of the test, whereas positive predictive value (and the ratio of false-positives to true cases) is dependent on the frequency of the conditionthe rarer the condition, the higher the ratio of false-positives to true-positives. There are 51 false-positives for each case of hypothyroidism. For galactosemia and congenital adrenal hyperplasia the ratio of false-positives per case is in excess of 180. Each positive screening test means an alarmed family and requires follow-up to identify the truly positive (for intervention) and alleviate the concerns of the false-positives.

Sequencing of the human genome will result in identification of a large number of base-pair sequences associated with abnormalities that may be treatable. Tests will certainly be developed to screen for many of these abnormalities, some of which will be very rare. As the tests are used, the amount of follow-up necessary will increase dramatically, even with highly sensitive and specific tests.

Someone has to pay for follow-up, and the burden commonly falls on public institutions such as health departments. If they are required to follow-up positive screens for a very rare condition, they will not be able, without additional resources, to carry out other needed functions (eg, immunizations, ensuring safety of the water supply) that affect much greater numbers of people. Consequently, economic/resource issues must be taken into account along with the human considerations of how the truly affected might benefit and how those with false alarms might be harmed.

Alan R. Hinman, MD, MPH, FAAP
Task Force for Child Survival and Development
Decatur, Georgia 30030

REFERENCES

1. Howse JL, Katz M The importance of newborn screening. Pediatrics. 2000; 106:595 [Free Full Text]
2. Newborn Screening Committee, The Council of Regional Networks for Genetic Services (CORN). National Newborn Screening Report1995. Atlanta, GA: CORN; 1999
3. Kwon C, Farrell PM The magnitude and challenge of false-positive newborn screening test results. Arch Pediatr Adolesc Med. 2000; 154:714-718 [Abstract/Free Full Text]

In Reply.

Dr Hinman raises a number of important issues relating to newborn screening. He seems to agree with our call for equity and uniform quality of testing; however, he parts company with us when he argues that our demand for mandatory tests for very rare diseases is "uncritical" and not justifiable by cost-benefit considerations.

In calling for an enlarged number of universally applied newborn screening tests in the United States, we limited the demand to those conditions for which treatments are available and in which immediate initiation of treatment is necessary to prevent lifelong adverse consequences to the affected child. This, in our opinion, transcends the arguments Dr Hinman makes.

Analyses of costs/benefit ratios depend on the assumptions one makes. It is relatively easy to calculate the economic costs. Emotional currency is harder to put into the equation, but the most difficult value for which to account is cost to a child who could have been normal but was severely damaged by failure to apply available effective treatment. Dr Hinman also points to the emotional cost to a family confronted with a false-positive test until the question is resolved and their anxiety alleviated. Surely such transient anxiety, with a healthy child at the end of it, does not outweigh the entire lifetime that other families must spend caring for a severely damaged child whose disabilities could have been prevented.

Dr Hinman predicts that we shall face more and more conditions for which newborn screening will be possible and, therefore, if our call for mandatory tests is heeded, the problems will be increased. This may well be true. Our society bears many costs, health care among them. These costs should be reduced to a minimum possible, but not beyond that.

Dr Hinman argues that the costs associated with benefits for the majority must take precedence over the costs that benefit only few. This surely has not been the philosophy of our nation. If it were, we would not have organ transplants, intensive care units, or treatments for infertility. In our democracy, the rights of the few are protected along with the rights of the many. Children born with rare disorders that can be detected immediately and corrected, but which would be completely missed without a test, are entitled to this benefit, and its cost should not be subtracted from those that benefit the majority. Civilized life is not a zero sum game.

Jennifer Howse, PhD
Michael Katz, MD
March of Dimes Birth Defects Foundation
White Plains, NY 10605