YY/T 1721-2020 English PDF (YYT1721-2020)

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YY/T 1721-2020: Free thyroxine (FT4) testing kit
YY/T 1721-2020
YY
PHARMACEUTICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 11.100
C 44
Free thyroxine (FT4) testing kit
ISSUED ON: JUNE 30, 2020
IMPLEMENTED ON: DECEMBER 01, 2021
Issued by: National Medical Products Administration
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Classification ... 4
4 Requirements ... 5
5 Test methods ... 7
6 Labels and instructions ... 9
7 Packaging, transportation and storage ... 9
Bibliography ... 11
Free thyroxine (FT4) testing kit
1 Scope
This Standard specifies the classification, requirements, test methods, labeling,
instructions for use, packaging, transportation and storage of free thyroxine testing kit
(hereinafter referred to as FT4 testing kit).
This Standard applies to immunoassay kits for the in vitro quantitative determination
of free thyroxine (FT4) using enzyme labeling, (electro) chemiluminescence labeling,
(time-resolved) fluorescence labeling, and other methods, using DAS-ELISA or
competition method as the principle.
This Standard does not apply to:
a) Reagents for qualitative or semi-quantitative determination of free human
thyroxine labeled with colloidal gold or other methods (such as test strips,
biochips, etc.);
b) Various radioimmunoassay or immunoradioactive testing kits labeled with
radioisotopes such as 125I;
c) Free thyroxine calibrators and free thyroxine quality controls intended for sale
individually or as part of the FT4 testing kit.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the dated version applies to this document. For
undated references, the latest edition (including all amendments) applies to this
document.
GB/T 21415-2008, In vitro diagnostic medical devices - Measurement of
quantities in biological samples - Metrological traceability of values assigned to
calibrators and control materials
GB/T 29791.2, In vitro diagnostic medical devices - Information supplied by the
manufacturer (labelling) - Part 2: In vitro diagnostic reagents for professional use
3 Classification
According to different labeling methods, it can be divided into enzyme labeling, (electro)
chemiluminescence labeling, (time-resolved) fluorescence labeling, etc. According to
Within the linearity range of the FT4 testing kit, test (2 ~ 3) quality-controlled samples
of different concentrations and repeat the test 10 times. The coefficient of variation (CV)
shall not be greater than 15%.
4.7 Batch difference
Within the linearity range of the FT4 testing kit, use three batches of testing kits to
detect high and low concentration samples, and the inter-batch coefficient of variation
between the three batches of testing kits shall be CV ≤15%.
4.8 Analytical specificity
Manufacturers shall stipulate the analytical specificity of the FT4 testing kit and clearly
explain it in technical materials such as the product manual. The results of the
determination of samples like 3,5,3'-triiodothyronine with a concentration not less than
200 ng/mL, 3,3',5'-triiodothyronine of 100 ng/mL and 3,3'-diiodothyronine of 200
ng/mL shall not be higher than the limit value claimed by the FT4 testing kit.
Note: The types and concentrations of potential cross-reactive substances are not
limited to the above statements.
4.9 Stability
Any of the following methods can be used for verification:
a) Valid period stability: The manufacturer shall specify the valid period of the
reagent (kit). Test the accuracy, detection-limit, linearity and repeatability of
the testing kit at the end of the valid period, which shall meet the requirements
of 4.3 ~ 4.6;
Note: Generally, when the valid period is 1 year, choose products that are no longer
than 1 month; when the valid period is half a year, choose products that are no
longer than half a month, and so on. However, if the specified time is exceeded,
it is acceptable if the product meets the requirements.
b) Thermal stability test: Place the testing kit within its valid period at 37 °C for
a certain period of time, to test the accuracy, detection limit, linearity and
repeatability, which shall meet the requirements of 4.3 ~ 4.6.
Note 1: Thermal stability tests cannot be used directly to deduce product valid period
unless a derivation formula based on a large amount of stability research data
is used.
Note 2: According to product characteristics, any combination of a), b) methods can
be selected; but the selected method should be able to verify the stability of the
product, so as to ensure that the product performance within the valid period
meets the standard requirements.
5 Test methods
5.1 Appearance
Visually inspect under natural light with normal or corrected vision, which shall meet
the requirements of 4.1.
5.2 Traceability
The traceability information provided by the manufacturer shall comply with the
requirements of 4.2.
5.3 linearity
Test the linearity samples specified by the manufacturer. The number of linearity
samples should be no less than 5. The low value should be close to the lower limit of
the linearity interval, and the high value should be close to the upper limit of the
linearity interval. Repeat the measurement for each sample at least twice; take the mean
of the measurement results; perform a straight-line fit with the labeled value or
theoretical value of the linearity sample to obtain the linearity correlation coefficient r.
The result shall meet the requirements of 4.3.
5.4 Detection-limit
Manufacturers shall provide relevant information such as the blank limit, detection limit
and reference range of the FT4 testing kit. Based on the information provided by the
manufacturer, test 5 low-value samples with concentrations close to the LOD. Test each
sample 5 times and sort the test results by size. If the following conditions are met, it
can be considered that the blank limit and detection limit provided by the manufacturer
are basically reasonable and the results meet the requirements of 4.4.
a) The number of test results that are lower than the blank limit value provided
by the manufacturer shall be less than or equal to 3;
b) There is no test result value higher than the lower limit of the reference interval
provided by the manufacturer.
5.5 Accuracy
One of the test methods may be selected in the following order of preference:
a) Based on the linearity range of the testing kit provided by the manufacturer,
use the reference material that can be used to evaluate the conventional method
as the sample, reasonably set 2 ~ 3 concentrations, and test it according to the
steps in the testing kit instructions. Repeat the test for each sample 3 times,
and record the test results as (Xi). Calculate the relative deviation (Bi)
according to Formula (1). If all three results meet the requirements of 4.5a),