Relative Usefulness of Three Growth Hormone Stimulation Screening Tests

Abstract

\s=b\One hundred ninety-one children were tested by one of three screening procedures for growth hormone deficiency over a five-year period. Sleep screen yielded a 31.3% false-positive rate; levodopa administration alone yielded a 20.5% false-positive rate and levodopa in combination with propranolol yielded a 5.2% false-positve rate. These results support the view that the combined levodopa\p=n-\propranololhydrochloride screen test is superior to either the sleep or the levodopa screen tests in limiting the number of false-positive results and thus the need for further, more extensive testing.(Am J Dis Child 133: [931][932][933] 1979) When growth and skeletal matu¬ ration rates are subnormal, growth hormone (GH) deficiency must be tested for if, as is frequently the case, no other causes for the growth retardation can be found. Only a small number of subjects will be GH deficient,1 and it is important to have a simple screening test available to eliminate from further testing the large majority of those with normal GH hormone secretion.A number of provocative tests have been devised to evaluate the pituitary GH reserve.-' ' This is a report of our experience with three of these tests, sleep, levodopa, and levodopa plus propranolol hydrochloride, as used in our institution over the past five years. MATERIALS AND METHODS Subject SelectionA total of 191 children referred to the UCLA Center for Health Sciences between June 1973 and June 1978 for evaluation of possible GH deficiency were tested. Chil¬ dren whose original referring diagnosis was short stature were tested only if their stature and bone age were more than 2 SD below the mean, and if the growth rate in children over 3 years of age was less than 5.0 cm/yr. Patients referred for complete evaluation of hypothalamic pituitary (H-P) function with known or suspected brain tumors (eg, craniopharyngioma, chromophobe adenoma, etc), severe organic illness, or other conditions known to affect the H-P axis (eg, anorexia nervosa), did not need to meet all these criteria.Sleep Screen.-Patients tested as outpa¬ tients were brought into our clinic emer¬ gency room at their usual bedtime and placed in a quiet room. Sixty to 90 minutes (average, 75 minutes) after the parents reported the onset of sleep, the patient was awakened, and a single venous blood sample was obtained. Inpatients were observed for the onset of sleep, and blood samples were similarly obtained. A total of 103 samples for GH determinations were so obtained from 97 different patients.Levodopa Screen.-Testing was per¬ formed after an overnight fast. Outpa¬ tients and inpatients were tested between 8:00 and 8:30 am. Levodopa was adminis¬ tered in a dose of 125 mg to subjects weighing less than 10 kg, 250 mg to those weighing between 10 and 30 kg, and 500 mg to those weighing more than 30 kg. Two blood samples were drawn, one at 60 and one at 90 minutes after ingestion of levodopa. A total of 43 patients were tested by this method.Levodopa-Propranolol.-After an over¬ night fast, levodopa was administere...

Growth Related Hormones in Idiopathic Scoliosis:An Endocrine Basis for Accelerated Growth

“…Fass et al (1979) found a markedly lower number of false positive results in the combined test compared to the Ldopa test and the sleep screen test. It has been shown that there is a significant correlation between standard pharmacological stimulation tests and the physiological 24-hour integrated serum concentration of growth hormone (Plotnik et al 1979).…”

Effect of Hypersomatostatinemia on Growth Hormone Secretion in Cystic Fibrosis Patients with Diabetes

“…Subjects were allowed to relax for at least 30 min before blood sampling to avoid stress effects on pituitary hormone release. A 10% solution of arginine-HCI was then infused intravenously over 30 min at a dosage of 0.5 g/kg to a maximum of 30 g [12,13]. Blood samples for mea surement of somatostatin and GH were then drawn at baseline and 15, 30,45 and 60 min after arginine was begun.…”

Recombinant human growth hormone treatment of children with chronic renal failure: long-term (1- to 3-year) outcome

“…Blood was taken from patients 1-7 at 30-min intervals over a 24-h period for GH estimation prior to initiation of the rhGH treatment. In addition, patients 1-8 underwent an L-DOPA/propranolol GH stimulation test as described by Fass et al [9]. The latter was performed prior to initiation of rhGH treatment in patients 6-8 and at the end of 1 year of rhGH treatment following discontinuation of treatment for 10 days in patients 1-5.…”