HPLC analysis of HbA1c in dried blood spot samples (DBS): a reliable future for diabetes monitoring.

To simplify collection and transport of blood for HbA1c measuring, we have studied the use of a special paper that absorbs a defined volume of capillary blood and quickly dries it (dried blood-spot, DBS). The DBS can be sent to a central laboratory using regular postal service and without temperature control. This system differs greatly from other proposed DBS methods for HbA1c because it overcomes the haemoglobin alterations during the drying and storing processes, that otherwise make this analysis unreliable. We have developed a special treatment of the paper before collection that stabilises the HbA1c molecule excellently in dried blood samples, allowing accurate HPLC analysis even two weeks after collection. This method has been applied in a "blind" study in which HbA1c values determined in 97 DBS coming from an hospital diabetes care centre were compared with those obtained from parallel venous blood samples.

The acid-labile subunit of human ternary insulin-like growth factor-binding protein complex in girls with central precocious puberty before and during gonadotropin-releasing hormone analog therapy.

The aim of the study was to evaluate serum acid-labile subunit (ALS) concentrations and their relationship with other parameters of the human ternary IGF-I-binding protein (IGFBP) complex in girls with central precocious puberty (CPP) before and after pharmacological arrest of puberty. We studied serum ALS, free IGF-I, total IGF-I, IGFBP-3 levels and IGFBP-3 protease activity in 13 girls, aged 1.6-7.8 yr (mean, 5.9 +/- 2.2), diagnosed as having CPP before and after 6 and 12 months of GnRH analog (GnRHa) therapy. The ALS SD score before treatment was high (1.4 +/- 0.72) and decreased significantly after 6 and 12 months of GnRHa therapy [0.4 +/- 0.54 (P < 0.01) and -0.4 +/- 0.61 (P < 0.01), respectively]. Serum IGF-I and IGFBP-3 were also increased before treatment, but both of these factors remained elevated after 6 and 12 months of GnRH-A therapy [IGF-I SD score, 3.20 +/- 1.64, 2.92 +/- 1.82, and 3.68 +/- 1.94 (P = NS), respectively; IGFBP-3 SD score, 1.02 +/- 0.53, 0.94 +/- 0.68, and 1.22 +/- 0.87 (P = NS), respectively]. Serum free IGF-I levels and IGFBP-3 proteolytic activity did not vary significantly from their pretreatment values during GnRHa therapy. In conclusion, serum ALS levels were elevated in girls with CPP and decreased significantly during the first year of GnRHa therapy. Serum IGF-I and IGFBP-3 levels were also increased before therapy, but their levels were not influenced by treatment. The ALS decrease seems to be the sole GH-dependent factor that parallels the decreases in steroid levels and growth velocity during GnRHa therapy.