The effect of sample storage on the reliability of thyroglobulin and thyroglobulin-antibody measurements

Area of Science:

• Clinical Chemistry
• Endocrinology
• Laboratory Medicine

Background:

• Thyroglobulin (Tg) and thyroglobulin-antibody (TgAb) are critical biomarkers in thyroid disease management.
• Accurate measurement of these analytes is essential for diagnosis and monitoring.
• Sample storage conditions can potentially influence analyte stability and assay results.

Purpose of the Study:

• To evaluate the impact of varying storage durations and temperatures on the immunoreactivity of thyroglobulin (Tg) and thyroglobulin-antibody (TgAb).
• To determine optimal storage conditions to maintain the integrity of Tg and TgAb measurements.

Main Methods:

• Thyroglobulin (Tg) and thyroglobulin-antibody (TgAb) levels were measured after storage under different time and temperature conditions.
• Samples were stored at 4-10 degrees C and -17 to -20 degrees C for varying durations.

Main Results:

• Storage at 4-10 degrees C for 48 hours increased Tg immunoreactivity by up to +23% and decreased TgAb by up to -16%.
• Storage at -17 to -20 degrees C for 4 weeks decreased both Tg and TgAb immunoreactivity by a maximum of 21-31%.
• Short-term (8 hours) room temperature storage did not significantly alter Tg and TgAb immunoreactivity.

Conclusions:

• Storage of samples at 4-10 degrees C for more than 24-48 hours significantly alters Tg and TgAb immunoreactivity.
• Storage at -17 to -20 degrees C for more than 2-3 weeks also significantly alters Tg and TgAb immunoreactivity.
• These findings highlight the importance of adhering to specific pre-analytical storage guidelines for accurate thyroid biomarker testing.