4. Anticoagulants

Blood and bone marrow aspirate (BMA) specimens should be collected using appropriate anticoagulant tubes or tubes containing other additives. The choice of test tube additives should be based on the type of analyte, test, and sample size. Studies have shown that heparin and heme may inhibit the 

 Make a PCR reaction. Therefore, EDTA and ACD anticoagulants are recommended for testing plasma or bone marrow aspirate specimens. If measured as intracellular RNA, the device used to collect blood or bone marrow should contain an RNA stabilizer, or an RNA stabilizer solution should be added immediately after collection.

5. Tissue Specimens

Tissue specimens can be used if blood or oral mucosal cells cannot be obtained (eg, if the patient died), or if the genotype of the tissue specimen is different from that of blood or oral mucosal cells, or if the tissue is the source of nucleic acid for some potentially infectious substances. Generally, the optimal amount of tissue is 1-2 g, but since the amount of DNA and RNA contained in each tissue varies, the amount of tissue collected varies from tissue to tissue. Multicellular tissues such as bone marrow, lymph nodes, and spleen are suitable for genomic DNA testing and require less tissue. Few-cell specimens such as muscle, fiber, and adipose tissue are not a good source of genomic DNA, and the collection amount is greater than 1-2g. Typically, at least 10 μg of RNA or DNA is obtained for tissues larger than 10 mg if there is no extensive fatty infiltration. The amount and type of protein varies from tissue to tissue, and nucleic acid isolation methods also vary from tissue to tissue. For the tissue of specific origin, isolate DNA or RNA according to the manufacturer's recommendations.

Pathologists usually take a representative part of the tissue from a large piece of tissue for fixation, staining, microscopy and pathological diagnosis, or select representative tissue to extract DNA or RNA for molecular analysis. Generally, lesion tissue is selected for detection, and non-lesion tissue is used as control. Control tissues are critical for certain molecular assays, such as loss of heterozygosity assays or microsatellite instability assays.