What are the components of trace elements? Procurement standards and query methods

At present, there is no unified, accurate international standard for trace element testing. Different hospitals may have different data, because different testing instruments and different reagents have different reference values, so the results may differ. In addition, the results of trace element testing are only a reference value, and there are also many factors that affect the trace element measurement results. A deficiency of trace elements certainly needs to be supplemented, but data reports should be combined with clinical symptoms; one should not simply take the test results as gospel and blindly give supplements to a child. The key is to see whether the child's physical condition has improved.

1. Blood

For blood sample collection, venous blood or capillary blood may be taken.

The content of trace elements in the human body is relatively low, and samples are easily contaminated by various sources during collection, so blood samples for trace elements require extra care during collection. In addition to the requirements for sample collection set out in the Ministry of Health's "Technical Specifications for Clinical Blood Lead Testing", special testing tubes for trace elements that have passed regular spot checks must also be used, and the test tube should immediately be sealed with inert and non-polluting material to eliminate the influence of the container itself on the test results.

Blood testing is prone to contamination, can cause cross-infection, and sampling is inconvenient; it reflects the body's trace element status over a short period and is greatly affected by diet and disease, so it serves only as clinical guidance.

2. Hair

Human hair includes head hair, underarm hair, beard, chest hair, etc., among which head hair testing is the most widely used:

(1) Hair samples are easy to collect and easy to store.

(2) As for trace elements, their content in hair is higher than in other parts of the human body such as blood, saliva and urine because of accumulation, and it is relatively stable and easier to analyze.

(3) Hair can reflect the trace element nutritional status of the past several weeks to several months, and thus can truly reflect the storage status of trace elements.

(4) The protein structure of hair can combine with elements in the environment such as water and the atmosphere, and its binding force varies with each trace element; therefore, trace elements in hair can also serve as an indicator of environmental pollution. This also shows that hair testing cannot represent the true level of trace elements in the body. Medical institutions generally do not use hair testing.