Development of a newborn screening laboratory quality assurance system in Shandong, China.

Shandong is a large province in northeastern China with a population of over 80 million. There are over 800,000 births annually with newborn screening testing currently being performed in 15 laboratories in city maternity and child health care hospitals. Since 1996, the number of newborns screened has steadily increased until the number screened annually now exceeds 600,000 (over 70%). During the period from 1996--2000, there were 97 cases of classical PKU confirmed and 399 cases of congenital hypothyroidism giving incidences of 1:11,644 and 1:2,831 respectively. The large number of newborns screened and the relatively large number of screening laboratories presents a quality control challenge since ideally each newborn should receive identical newborn screening services and the laboratories should be of equal abilities. With assistance from the US Centers for Disease Control (CDC), a provincial laboratory quality control program has been established and provides oversight for a newborn screening system from blood collection through treatment of patients. The goal is to ensure that patients with the disorders of interest can be identified from within the normal newborn population with an acceptable minimum number of false positives while attempting to eliminate false negatives. External proficiency testing materials are provided quarterly by the CDC, repackaged by the Center for Newborn Screening Quality Control of Shandong (CNQCS), and distributed to the testing laboratories. Analytical results are reported within a specified period of time and then compared to CDC reported results. Laboratories unable to analyze the samples correctly are provided technical assistance. Additionally, the CNQCS oversees and provides educational assistance in training phlebotomists and other health workers associated with newborn screening. Brochures, posters, videotapes and parent support groups are also developed as a function of the CNQCS. Ultimately, control materials will be prepared for distribution with linkages to CDC for international comparability.

The investigation of factors influencing the measurement of thyroid stimulating hormone in dried blood spots on filter paper.

We investigated sample collection variables that may influence the measurement of the thyroid stimulating hormone (TSH) including: time after birth, season, different ways for blood spot drying and varied elution time from filter paper. TSH was measured with an enzyme-linked immunoassay (EIA) method on dried blood spots collected from newborns and/or external quality control materials from CDC. We found that TSH results were stable if specimens were collected from newborns 72 hours after birth. We obtained different results when TSH was measured during different seasons. The results also changed as the specimens were dried in different ways. The length of time for eluting from the DBS also exerted influence on the TSH measurement. In order to assure newborn screening quality, all factors influencing the results should be considered and the best condition for testing chosen. The specimen should be collected from babies at 3-6 days of age and air-dried at room temperature. Different cut-offs may be necessary for different seasons of the years.