YY/T 1724-2020 in English

Analysis of the core content of the standard

This standard specifies the technical requirements and quality control system of the FT3 test kit, focusing on the three mainstream detection technologies of enzyme labeling, chemiluminescent labeling and fluorescent labeling. Its core performance indicators include:

Detailed explanation of key technical requirements

4.3 Linearity verification

The standard requires verification by linear fitting, and it is recommended to select concentration points that include clinical decision values (such as the upper and lower limits of the reference interval). In practical applications, please note:

• It is recommended to add 7-8 concentration points for enzyme-labeled assay reagents
• The chemiluminescence method needs to pay attention to the high-dose hook effect

4.8 Analytical specificity

Explicitly require verification of cross-reactions of substances such as thyroid hormone (≥200ng/mL):

Implementation recommendations

Precautions for manufacturers

1. Traceability documents must include uncertainty analysis of calibrator assignments
2. A combination of accelerated aging test and real-time stability is recommended for stability verification
3. Analytical specificity statements should be consistent with the CLSI EP07-A2 guideline

Laboratory application recommendations

When conducting FT3 testing, please note:

• Calibrators of different methodological kits cannot be mixed
• Batch difference monitoring should be performed every month (CV≤15%)
• Abnormal results require investigation of hemolysis/lipidemia interference

Standard Evolution Analysis

Compared with previous versions, the 2020 version has the following major updates:

• Added electrochemiluminescence labeling methodology classification
• Refine the time conversion rules for thermal stability verification
• Clarify that the concentration of quality control products should cover the medical decision level