How long does it take to transport, store, and examine blood routine?
★ In the Expert Consensus on Standardization of Transport and Preservation of Clinical Laboratory Samples 2023: It is mentioned that the transportation time limit requirements for blood routine, blood type, erythrocyte sedimentation rate, etc. are less than 8 hours, refrigeration is less than 24 hours, Plasmodium is less than 1 hour, and the specimen storage time is refrigeration for 1-7 days, blood smear for 2 weeks, and blood type for 1 month.
★ WS/T 806-2022 Basic Technical Standards for Clinical Blood and Body Fluid Testing: Clinical specimens for blood cell analysis should be tested within 8 hours after collection. For venous blood specimens for Plasmodium examination, thick and thin slices should be prepared at the same time within 1 hour after collection. If the slice is not prepared within 1 hour after blood collection, it must be marked in the report.
★ The specimens in the laboratory are basically more in the morning, and the abnormal specimens are more concentrated. In clinical practice, the TAT of blood routine is basically 30min to 60min (except for special specimens). Therefore, it is not recommended to test specimens for 3 days (except for special specimens).
Long-term storage of specimens will affect the test results
★ Studies have shown that: at room temperature (25℃), after more than 4 hours, MCV and MCHC will increase due to the increase in storage time of blood specimens. This may be because the blood cells are in a hypertonic state, which leads to an increase in osmotic pressure; after the blood is mixed with a hypotonic diluent, the red blood cells will lose water, resulting in an increase in MCV, and after the red blood cell volume increases, the average hemoglobin concentration of red blood cells will also increase. 24 hours of storage at room temperature has the greatest impact on platelets. Platelets are unstable and easily affected by storage time and storage temperature. It may be that platelets themselves have aggregation characteristics and form larger particles. In sensitive automated blood analyzers, only cell size can be identified, ignoring the properties of cells, resulting in large differences in platelets at different storage times and temperatures.
★ Studies have shown that when the room temperature is kept at 20~25℃, the specimen is placed within 6 hours, which does not significantly change the white blood cell, red blood cell, platelet and hemoglobin levels in blood routine tests. However, as time goes by, PLT (platelets) tends to increase, and changes significantly earlier than other indicators. This change may be related to factors such as the morphological changes of platelets. The change of MPV may be related to the release of chemical substances after PLT contacts the container, adhesion and aggregation, and the increase in osmotic pressure in the solute makes the volume of PLT larger, causing the MPV test result to increase. Platelet aggregate products are counted in the white blood cell count range, resulting in a gradual increase in WBC count.
★For morphology, blood smear cells of old specimens are prone to shrinkage or pseudospheres, pseudothorns or vacuolar degeneration, granule shedding, and cell swelling and rupture.