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Abstract

This article shifts the focus from traditional "drug administration" to "blood collection," delving into the core technological applications of subcutaneous injection needles and their systems in clinical diagnostics. It covers vacuum blood collection systems, micro-volume blood sampling techniques, and cutting-edge minimally invasive continuous monitoring, highlighting their irreplaceable role as an "information gateway" for disease diagnosis.

Main text

Another equally important role of subcutaneous injection needles is to serve as "messengers of information," collecting various biological samples from the human body for diagnostic purposes, with blood being the most critical. Over 70% of modern laboratory diagnostics rely on blood analysis, and safely, efficiently, and standardized collection of blood samples represents the first crucial step in ensuring accurate test results. This cannot be achieved without innovation in professional blood collection devices and systems.

The vacuum blood collection system is a prime example. It consists of a multifunctional needle holder, disposable dual-directional blood collection needle, and vacuum tubes preloaded with additives. Its working principle is ingeniously designed: after the needle pierces the vein, the hidden tip at the other end penetrates the rubber stopper of the vacuum tube under protection from the holder, and the preset negative pressure within the tube automatically draws blood smoothly into the tube. Its advantages are revolutionary:

Standardization: Different colored caps correspond to specific additives (anticoagulants, clot activators, etc.) and precise blood volumes, ensuring sample quality.

Biosafety: Blood flows entirely within a closed system from the patient to the tube, greatly protecting healthcare workers.

High efficiency: Multiple tubes can be collected in a single puncture, reducing patient discomfort.

High quality: Avoids hemolysis that may occur with traditional syringe aspiration.

For special populations and specific needs, blood collection needles feature more refined designs. Micro-volume blood collection needles designed for newborns and infants-such as heel-prick or capillary needles-have extremely short tips that penetrate only the superficial capillary network, enabling multiple screenings with minimal blood volume. Arterial blood gas sampling needles are equipped with a unique self-filling mechanism that uses arterial pressure to automatically draw blood into the syringe. These needles also contain preloaded lithium heparin anticoagulant to prevent sample coagulation, which is critical for monitoring respiratory and metabolic status in critically ill patients.

At the forefront of diagnostics, the concept of subcutaneous injection needles is evolving toward minimally invasive and continuous monitoring. For instance, the probe of a continuous glucose monitoring system is essentially an ultra-thin, flexible sensor implanted beneath the skin, with an outer diameter comparable to that of the finest injection needle, capable of continuously monitoring interstitial glucose levels for up to 14 days. Although it does not draw blood, its "minimally invasive implantation" technology originates from needle design. Similarly, certain painless microsampling devices use laser or micro-needle arrays finer than a human hair to pierce the outermost layer of skin, collecting minute amounts of interstitial fluid for analysis-representing a potential future form of home-based monitoring.

In addition, in certain tissue biopsies (such as fine-needle aspiration cytology) and bone marrow aspirations, specially reinforced biopsy needles are also essential tools for obtaining pathological diagnostic samples, with designs that emphasize tissue integrity and procedural stability.

Conclusion

In the field of diagnostics, subcutaneous injection needles have evolved from simple "piercing devices" into sophisticated sample collection platforms integrating precision engineering, materials science, and fluid control. They ensure that the "flow of information" from the human body to the laboratory is transmitted in the safest, most standardized, and least invasive manner possible, forming an indispensable cornerstone of precise diagnostics-its value being as significant as that of its "drug delivery" function.