BS ISO 20495:2018,Traditional Chinese medicine — Skin electrical resistance measurement devices.BS ISO 20495:2018 pdf free download here.The size is 1.52M.
ISO 20495:2018 specifies performance and test methods for skin electrical resistance measurement devices.

ISO 20495:2018 is applicable to skin electrical resistance measurement devices through which an electrical signal is applied on acupuncture points of the human body or specific points of the body surface in a non-invasive way so as to detect the resistance of the body.

ISO 20495:2018 is not applicable to software or functions for medical analysis of the test results.

Additional guidance and rationale are given in Annex A.
4.2 Accuracy of measurement
he error between any measured value and actual value shall be no more than +10 %.The measured value may be expressed as electrical resistance,voltage (V),current (A) or a relative value.
Conformity is determined by carrying out the following test.
Within the measuring range of skin electrical resistance specified by manufacturers, choose five measuring values including boundary values for detection. For a device with multiple measuring ranges, each measuring is tested separately. Choose five measuring values including boundary ne for detection specified by manufacturers within each measuring range.
Measure the resistance on the equivalent circuit of five measuring values for more than five times, non-reactive 1% resistor corresponding as close as possible to each of the measuring points selected. Each measured value shall be within +10% of the stated value ofthe selected resistor.