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Newborn screening
Basics the nurse needs to know
Newborn screening detects disorders that are present at birth but the disorders demonstrate no immediate symptoms. If undetected and untreated, these disorders will result in significant mental retardation, developmental disability, or death. The permanent damage usually occurs within months of birth. One of the selection criteria of a newborn screening test is that the disorder must have effective treatment that can limit the symptoms of illness and prevent disability before it occurs (Gilbert-Barnes, Kapur, Oligny & Siebert, 2007).
Testing for PKU and hypothyroidism are mandatory in all states of this country, but among all the states there is considerable variation regarding other tests that are included in mandatory newborn screening. The diseases that are more commonly assessed by newborn screening are presented in Box 7. In general, the tests include those for cystic fibrosis, selected endocrine tests, selected hemoglobin disorders, and selected disorders of metabolism. In some states, a mandatory screening test for hearing also is done, but since the method is not done by a laboratory test, the topic is beyond the scope of this book.
All screening tests have a somewhat high percentage of false-positive results. A false positive means that the test demonstrated a positive result, but the infant does not have the disease. False-negative results may also occur. False negative means that the infant has the disease, but the laboratory screening test was negative. When there is medical doubt about the screening test result, a repeat screening test may be done in 7 days. Positive screening tests are always followed up with more specific testing to confirm or exclude the final diagnosis.
Nuclear scan
Basics the nurse needs to know
In a nuclear scan, the source of the radiation is a radionuclide, a radioactive isotope that has a short half-life. This means that the isotope emits gamma rays or photons for a few hours and then loses strength. By the time it is excreted in urine or feces, the radioactivity is greatly reduced or negligible. Technetium (Tc 99m) is one of the most common radionuclides. Others include isotopes of iodine, xenon, gallium, indium, and thallium for scans of specific organs or locations. In nuclear scanning, the radioisotope that is bound to a specific compound is called a radiopharmaceutical. When administered orally or intravenously to the patient, the radiopharmaceutical is taken up or absorbed by the target tissue or organ. The targeted tissue concentrates the radiopharmaceutical and emits radiation that is detected and imaged by the scanner or camera. Some of these scans, their purposes, and the pertinent patient care information are presented in Table 11.
Table 11 Selected Nuclear Scans
Name of Scan | Purpose | Special Patient Care Measures |
Brain scan (positron emission tomography [PET] scan) | To evaluate brain tissue metabolism and function, with detection of abnormalities such as dementia, stroke, atherosclerosis, epilepsy, Alzheimer’s disease; | ![]() Stay updated, free articles. Join our Telegram channel![]() Full access? Get Clinical Tree![]() ![]() ![]() |