Home monitoring of 17 alpha-hydroxyprogesterone levels by filter paper blood spots in patients with 21-hydroxylase deficiency

BACKGROUND: 21-Hydroxylase (21-OH) deficiency is characterized by an excess of androgen in both sexes and premature skeletal maturation resulting in short adult stature and male infertility. To achieve optimal height in children and fertility in adults, the replacement treatment of 21-OH deficiency with glucocorticoids should be regulated in order to adequately reduce the excess of androgens while minimizing the dose of glucocorticoids required. Neonatal screening for 21-OH deficiency is based on the measurement of the 17 alpha-hydroxyprogesterone (17-OHP) level from blood spotted on filter paper. The aim of this study was to examine whether repeated daily blood sampling on filter paper can assist in improving the monitoring of, and compliance to, 21-OH deficiency treatment. METHODS: During a 5-year period (1989-1994) we instructed 8 patients with 21-OH deficiency (2 males with salt losing, 2 males and 1 female simple virilizing, and 1 male and 2 females with nonclassical 21-OH deficiency) aged 1.3-36 years to sample blood on filter papers 1-4 times a day and send the papers to our neonatal screening laboratory by mail. On 62 occasions we measured both serum and filter paper 17-OHP levels in order to assess the degree of correlation between the two methods. RESULTS: Comparison between the filter paper and serum 17-OHP levels showed a correlation coefficient of r = 0.87. The filter paper levels were almost always higher than the serum levels. The serum 17-OHP levels were < 1 ng/ml whenever the filter paper levels were < 3 ng/ml. On long-term follow-up of 17-OHP filter paper levels we observed major diurnal and day-to-day fluctuations which might not have been noticed on routine follow-up clinic visits. CONCLUSIONS: Filter paper follow-up of 17-OHP levels can assist in optimizing the replacement treatment in patients with 21-OH deficiency while reinforcing compliance and decreasing the need for frequent clinic visits and hospitalizations. By adjusting the glucocorticoid type, dose, and time of administration to each patient we should be able to achieve optimal growth without bone age acceleration in children, to avoid overtreatment, and to improve fertility in adults.