High-quality domestically produced vacuum blood collection tubes are gradually replacing their imported counterparts.
Release time:
2013-07-25
Overview:
Vacuum blood collection tubes serve as both specimen collection tubes and testing tubes. The precisely controlled vacuum within the collection tube provides the driving force for the blood-collection process and ensures quantitative sample collection.
Today, domestically produced vacuum blood collection tubes have taken a dominant position in the medical market. High-quality domestic vacuum blood collection tubes are gradually replacing their imported counterparts, and some brands have already fully entered the international market. Vacuum blood collection tubes are becoming increasingly popular, gradually replacing the traditional syringe-based blood-collection method. This shift has standardized blood-collection techniques, improved the quality and speed of specimen preparation, and enhanced overall testing efficiency. As a globally shared technology, China has made significant progress in both the manufacturing and application of vacuum blood collection tubes. Compared with traditional blood-collection methods, many unique advantages of vacuum blood collection tubes are clearly evident. If we gain a clear understanding of these technologies and features, we can make even better use of them. There are numerous factors that influence the quality of vacuum blood collection tubes; below, we will focus on four key aspects: the materials used in the tubes, additives, vacuum stability, and the配套 blood-collection needles and needle holders.
(TD5M-WS Fully Automatic Decapping Centrifuge and TD5A-WS Automatic Decapping Centrifuge, manufactured and supplied by Shanghai Luxiangyi Centrifuge Instrument Co., Ltd. For more details, please call our nationwide toll-free hotline at 400-8210-672 or 136 366 75110.)
I. Materials
The widespread use of automated instruments and the need to preserve blood samples have placed higher demands on the stability of the original characteristics of blood specimens. As a result, vacuum blood collection technology has gone beyond merely meeting safety requirements; its performance indicators—including accuracy, preservation of the specimen’s original characteristics, duration of stability, compatibility between tubes and collection devices, and tube strength—can all serve as criteria for evaluating the quality of vacuum blood collection tubes.
1. Material of vacuum blood collection tubes: Currently, most blood collection tubes are made of either ordinary glass or plastic. Ordinary glass tubes, due to their relatively high pH value, tend to cause hemolysis. Moreover, glass tubes produced using the drawn-tube process often feature densely packed linear grooves of varying depths and thicknesses, which can lead to cells adhering to the tube walls. At present, some companies have started using neutral glass (pharmaceutical-grade glass). Neutral glass boasts advantages such as high pressure resistance, minimal leaching, tightly arranged molecular structure, and fewer grooves when stretched. These tubes can withstand free-fall from heights exceeding 1.5 meters, effectively preventing specimen leakage during collection, transportation, and testing, thus avoiding environmental contamination and reducing the likelihood of needing repeat sampling. Additionally, the bottom of the tube has undergone special reinforcement treatment to prevent breakage during centrifugation. During the manufacturing process, vacuum blood collection tubes undergo an internal wall treatment in which silicone oil or emulsion is diluted according to a specific ratio and evenly coated onto the inner surface of the tube. Since silicone oil is an extremely inert compound, it adheres firmly to the inner wall of the tube, significantly reducing the adhesion between blood cells and the tube wall. Plastic vacuum blood collection tubes are made from PET plastic. PET plastic tubes offer the following advantages: they are lightweight and easy to transport; the likelihood of tube wall damage is extremely low, minimizing the risk of specimen leakage during transportation, centrifugation, and testing; and after use, they can be directly sterilized by high-pressure steam or incinerated for disposal. High-quality blood collection tubes have specially treated inner walls during injection molding, which effectively reduce the adhesion between blood cells and the tube walls, thereby decreasing the formation of fibrin strands.
2. Tube Compatibility: With the widespread adoption of automated biochemical analyzers and blood analyzers, only tubes with standardized outer diameters—13 (16) mm × 75 mm or 13 (16) mm × 100 mm—can be directly used on these instruments. However, the outer diameter of nationally standardized tubes is evidently too small. When such tubes are directly loaded onto the instrument, they cannot be securely fixed, leading to varying degrees of tilting. As a result, there is a higher likelihood of damage to the sampling needles. Currently, some domestic brands have already adjusted their standards to adopt uniform dimensions, making these tubes compatible with testing equipment from Hitachi, Beckman, Toshiba, Olympus, Shimadzu, Pharmacia, Coulter, Dong-A, Abbott, and Bayer, among others.
II. Additives
Additives include anticoagulants, procoagulants, buffers, protectants, inner-wall treatment agents, tube-mouth treatment agents, and separation gels. Their types, properties, and concentrations directly affect the characteristics of blood samples and the accuracy of test results. The following are some commonly used additives:
1. Biochemical type
Biochemical blood collection tubes are categorized into three types: additive-free tubes (red cap), clot-promoting tubes (orange cap), and separator gel tubes (yellow cap). High-quality additive-free blood collection tubes have a uniformly coated inner wall treatment agent and a tube-mouth treatment agent, which prevent cell lysis during centrifugation and ensure accurate test results. Moreover, the inner walls of these tubes and the serum they contain remain clear and transparent, with no blood residue adhering to the tube openings. In addition to the uniformly coated inner wall and tube-mouth treatments, clot-promoting tubes employ a spray-coating method to ensure that the clot-promoting agent is evenly distributed across the tube’s inner surface. This facilitates rapid and thorough mixing of the blood sample after collection, significantly shortening the clotting time and preventing fibrin filament formation, thereby avoiding blockages in equipment needles during sampling. During centrifugation, the separator gel in separator gel tubes liquefies and migrates to the center of the tube, forming a barrier between the serum or plasma and the formed elements of the blood. Once centrifugation is complete, the gel solidifies, completely separating the serum or plasma from the cellular components, thus ensuring the stability of the serum’s chemical composition and maintaining its integrity without significant changes for up to 48 hours when refrigerated. Inert separator gel tubes containing heparin can achieve rapid plasma separation and allow samples to be stored for extended periods. The aforementioned separator gel tubes are suitable for rapid biochemical assays. Separator gel-heparin tubes are particularly well-suited for emergency and intensive care unit (ICU) settings, where biochemical testing is frequently required. Compared to serum tubes, their greatest advantages are: first, the rapid separation of serum (or plasma); and second, the longer-term stability of the serum’s (or plasma’s) chemical composition, making them ideal for transportation.
2. Anticoagulants
1) Heparin tube (green cap): Heparin is an excellent anticoagulant that causes minimal interference with blood components, does not affect red blood cell volume, and does not induce hemolysis. It is suitable for performing red blood cell osmotic fragility tests, blood gas analysis, plasma osmolality measurements, hematocrit determination, erythrocyte sedimentation rate tests, and routine biochemical assays.
2) Blood Collection Tubes (Purple Cap): EDTA chelates calcium ions in the blood, thereby preventing clotting. Typically, 1.0 to 2.0 mg of EDTA can inhibit the coagulation of 1 ml of blood. This anticoagulant has no effect on white blood cell counts or cell size, minimally affects red blood cell morphology, and can also suppress platelet aggregation. It is suitable for routine hematological tests. Usually, the reagent is applied by spraying to ensure even coverage on the tube walls, facilitating rapid and thorough mixing of the blood sample after collection.
3) Coagulation Tubes (Blue Cap): These collection tubes contain a pre-measured, liquid sodium citrate anticoagulant buffer. The anticoagulant is added to the blood sample at a ratio of 1:9 relative to the prescribed blood volume and is used for coagulation-related tests (such as PT and APTT). The anticoagulant works by binding to calcium ions, forming a soluble calcium chelate that prevents blood from clotting. The recommended concentration of anticoagulant for coagulation assays is either 3.2% or 3.8%, equivalent to 0.109 or 0.129 mol/L, respectively. In blood coagulation testing, if the blood-to-anticoagulant ratio is too low, the APTT time will be prolonged, and the prothrombin time (PT) results will also be significantly affected. Therefore, ensuring that the anticoagulant-to-blood ratio is accurate is a critical factor determining the quality of these products.
4) Erythrocyte Sedimentation Rate Tube (Black Cap): The anticoagulant system of this blood collection tube is identical to that of a coagulation tube; however, sodium citrate anticoagulant is added at a ratio of 1:4 relative to the prescribed blood collection volume, and it is used for erythrocyte sedimentation rate testing.
5) Blood glucose tube (gray): This collection tube contains fluoride as an inhibitor. Thanks to the addition of the inhibitor and special treatment of the tube’s inner wall, the original characteristics of the blood sample are preserved for a longer period, and red blood cell metabolism is essentially halted. It is widely used for tests including blood glucose, glucose tolerance, red blood cell electrophoresis, alkali-resistant hemoglobin, and sugar-induced hemolysis.
3. Vacuum Degree
Vacuum blood collection tubes serve as both specimen collection containers and testing tubes. The precisely controlled vacuum within the collection tube provides the driving force for the blood-collection process and ensures quantitative sample collection. The accuracy of the vacuum level setting can significantly affect the test results. Below are several key factors that influence the vacuum level:
1) Ambient atmospheric pressure: The higher the altitude, the smaller the blood sample volume.
2) Ambient temperature: The higher the temperature, the lower the vacuum level and the smaller the blood collection volume; conversely, the lower the temperature, the greater the blood collection volume.
3) Product storage time: Generally speaking, the longer the storage period, the smaller the blood collection volume. This is mainly due to vacuum leaks occurring in the blood collection tubes and their sealing components.
4) Individual patient differences (such as venous pressure, blood viscosity, vascular condition, etc.): For example, excessive patient anxiety, elevated blood viscosity in chemotherapy patients, and vascular hardening can all lead to inaccurate blood collection volumes.
5) Blood collection techniques and associated blood-collection needle types—such as the selection of needle type, determination of the blood-collection endpoint, and choice of venipuncture site—can also lead to inaccurate blood-collection volumes if handled improperly.
4. Blood Collection Needles and Needle Holders
Currently, some domestic enterprises, due to their focus on the research and production of blood-collection systems, have seen their products become increasingly homogeneous with imported ones. These enterprises can provide users with excellent technical services and guaranteed product quality. For example, Chengdu Ruiqi Company, while manufacturing vacuum blood collection tubes, is also engaged in the research and production of blood-collection needles—including needle holders. A high-quality blood-collection needle must possess the following advantages:
1. The needle’s cutting edge, with its precise length and angle, is ideally suited for venipuncture. The cutting edge is exceptionally smooth, resulting in minimal discomfort and residual pain for patients after sampling.
2. The inner wall of the needle is exceptionally smooth, which not only speeds up blood collection but also prevents fragile blood cells from being adsorbed or damaged as they pass through quickly, thereby reducing cell damage. The ultra-thin needle wall minimizes tissue trauma caused by puncture, reduces the leakage of interstitial fluid, and enhances the quality of the collected sample.
3. The rubber sleeve on the side of the dual-direction needle and soft needle that is close to the blood collection tube can withstand 100 punctures without any liquid leakage. This allows for the collection of multiple samples from a single venipuncture, ensuring venipuncture safety while reducing patient discomfort and minimizing the workload of medical staff.
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