GADA are often detected by radioimmunoprecipitation assays, although nonradioactive formats are available.
At onset of type I diabetes, 1A-2A are not as common as ICA or GADA, being present in ~60% of subjects: however, IA-2A are more common, in general, than IAA.
GADA ve IA-2A'nin, ICA'ya kiyasla daha kolay olculebilmesi ve IAA'ya kiyasla [beta]-hucre otoimmunite-sini belirlemede daha duyarli olmasi nedeni ile tercih edilmesi onerilmektedir.
Bu nedenle, 5 yas altindaki hastalarda IAA ve GADA bakilip negatif bulunur ise, ve suphe devam ediyorsa ICA ve IA-2 antikoru icin test yapilmasi, >5 yas olanlarda taramaya IA-2 ve GAD antikorlari ile baslanip gerekirse ICA ile konfirme edilmesi, LADA suphesinde ise GADA bakilip gerekirse ICA ile konfirme edilmesi tavsiye edilebilir (15).
In young patients with new-onset T1DM (53), 63% were positive for ZnT8A (vs 72% positive for GADA, 68% positive for IA-2A, and 55% positive for IAA).
In young patients with new-onset T1DM who were negative for ICA, GADA, IA-2A, and IAA, 26% were positive for ZnT8A (53).
The mean recoveries were 96% for GADA and 97% for IA-2A when 3 replicates were used in each assay.
Correlation was strong between the antibody concentrations obtained by the dual- and single-label TR-IFMA GADA and IA-2A assays.
The ELISA and RBA GADA showed diagnostic specificities of 99% (95% CI, 93-100%) and 96 (89-99)%, respectively.
Passing-Bablok regression analysis for GADA yielded the following equation: ELISA = 0.
988; n = 200), when the GADA time-resolved fluorometric assays were performed blindly in two independent laboratories.
The observed vs calculated GADA concentrations were determined in four different dilutions.
ICA were found in 87, IA2-ab in 69, and GADA in 66 of the 100 patients.
Figure 2 shows the ROC curves obtained for the IA2-ab, GADA, and ICA assays, and for a combination of the IA2-ab and GADA assays made by logistic regression analysis, with the sensitivities determined from the results for the diabetic children (n = 100) and the specificities from the control children (n = 99; excluding the outlier).
The precision of the assays was monitored by including in each run two control samples in duplicates, one with a low concentration of GADA
and one with a high concentration.