A comprehensive understanding of traditional POCT and molecular diagnostic POCT concepts in one article

At present, the mainstream practice of nucleic acid testing in China still relies on the standard PCR laboratory environment, with operations carried out by professionals holding PCR work certificates. Moreover, strict zoning of PCR laboratories is required to effectively avoid cross-contamination and reduce biosafety risks. Although traditional testing methods can meet the requirements of clinical testing in terms of the number of test specimens, automated operation, result accuracy, and performance stability, they cannot be satisfied in terms of portability, detection speed, automated testing process, and no specific experimental conditions required. With the continuous improvement and development of clinical testing demands, POCT technology is advancing rapidly.

The "GB/T29790-2013 Requirements for Quality and Competence of Point-of-Care Testing" issued by the Standardization Administration of the People's Republic of China has determined a brand-new and correct Chinese name for POCT - Point-of-care testing.

Point-of-care testing (POCT), also known as "bedside testing" or "proximity testing", refers to tests conducted near or at the patient's location, whose results may lead to changes in the patient's treatment. It also refers to a testing method that is conducted on-site and uses portable analytical instruments and matching reagents to quickly obtain test results. POCT is an important field in the development of laboratory medicine, featuring three major advantages: rapid detection, on-site sampling, and simple operation. In the field of infectious disease screening, compared with traditional pathogen detection methods, POCT is faster and more sensitive in diagnosis. POCT, as an immediate testing method provided to patients in primary health care institutions and public health emergency treatment, plays an extremely important role in the prevention and control of infectious diseases, hospital infection management, and the improvement of health economic benefits. It has the potential to help improve the level of public health management.

The term "POCT" in the United States refers to medical tests conducted right at the patient's doorstep. In 1999, Hicks et al. defined POCT as a test close to the patient and classified it into two types: narrow and broad.

In fact, with the introduction of immune response and molecular biotechnology, the use of POCT has become more convenient, and the scope of detection and application has become wider.

At present, POCT can not only be used for blood glucose detection and early pregnancy detection, but also for the detection of cardiovascular diseases, acute and chronic kidney diseases, acid-base disorders, infectious diseases, blood diseases, coagulation disorders, and the monitoring of therapeutic drug concentrations, etc. The application sites have extended from accident scenes and homes to wards, outpatient departments, emergency departments, intensive care units, operating rooms, and even customs, community health stations, and private clinics. The application fields have also expanded from clinical practice to food hygiene, environmental monitoring, drug control, forensic science, etc.

The commonly used POCT techniques in the early stage mainly focused on qualitative detection, including colloidal gold, immunochromatography, dry chemical techniques, etc. Later on, with the development of technology and the gradual increase in the demand for detection results, POCT products centered on immunofluorescence, upforwarding, chemiluminescence, microfluidic technology, etc., developed rapidly and were gradually applied in clinical practice, achieving rapid quantitative detection and improving accuracy.

The World Health Organization (WHO) requires that newly established POCT methods should comply with the "ASSURED" standard. Namely, Affordable, Sensitive, Specific, User-friendly, Rapid and repeatable Robust, Equipment-free and Delivered (to the end user). This standard was first proposed in the WHO Special Program for Research and Training in Tropical Diseases. Meanwhile, POCT should be conducted by non-laboratory personnel both in laboratories and outside hospitals.

POCT is widely used in the United States. In 1995, the National Committee for Clinical Laboratory Standards (NCCLS) of the United States published the AST2-P document. Namely, the Point Of Care in vitro diagnostic Testing Proposed-Guideline to regulate POCT. It has now been accepted and applied by many other countries such as the United Kingdom, Japan, Sweden, Denmark, France, etc.

When the concept of POCT emerged in clinical practice, few people might have imagined that molecular diagnostics could also be POCT-ized. As is known to all, in recent years, both molecular POCT technology and traditional PCR technology have developed rapidly.

The increased requirements for detection time in clinical practice have led to technical predicaments for traditional PCR technology. Firstly, it has high requirements for the experimental environment and needs a standard PCR laboratory, which cannot meet the clinical emergency needs. Separate nucleic acid extraction and amplification can easily lead to contamination of samples or reagents. The operation steps are cumbersome and the detection cycle is relatively long. The need for professional technicians and other shortcomings have imposed certain limitations on traditional PCR in terms of time, space and personnel. The continuous upgrading of clinical requirements for diagnostic speed and convenience has led to the emergence of POCT.

Molecular POCT refers to a molecular biology detection system that is fully automatic and integrated through technological innovation and optimization to meet the requirements of point-in-care testing (POCT). This system is an integrated and closed system, where nucleic acid extraction and amplification detection are all completed on the same closed and portable instrument, without the need for manual reagent preparation or sample processing. From the time the samples are put on the machine to the process of result reporting, no other manual operations are required, which can effectively prevent biological samples and their genetic material from contaminating the environment. It also features miniaturization, portability, automation, full containment, high speed, and easy operation. At the same time, it can ensure high specificity and sensitivity of detection performance, making it applicable to various testing scenarios such as hospital emergency departments, primary medical institutions, families, customs, and disaster sites.

Molecular POCT diagnostic products can be applied to virus detection (influenza virus A/B, syncytial virus, novel coronavirus, HIV, HBV, HCV, etc.), bacterial and drug resistance detection (Mycobacterium tuberculosis and rifampicin resistance, multi-drug resistant bacteria CRE, Chlamydia trachomatis and Neisseria gonorrhoeae, Group B Streptococcus, etc.), and syndrome detection (diarrhea syndrome pathogen, bloodstream infection syndrome Detection of pathogens, respiratory tract infection pathogens, etc., as well as tumor genes. At present, almost all the project that traditional PCR technology can perform can also be carried out on the molecular POCT platform.

Molecular POCT nucleic acid testing eliminates many steps of regional specimen processing and large-scale instrument equipment testing, and also simplifies the cumbersome process of data processing. It can directly and quickly obtain reliable results to guide patient treatment, thus being applicable in both emergency response to major public health events and diagnosis, treatment and management of nosocomial infections. All have the prospects of providing important technical support and guarantee for precise treatment and scientific prevention and control.

The rapid development of POCT is not only a clinical need but also a result of technological advancement. Its development has made testing simpler and faster.

As an important component of experimental medicine, laboratory medicine has made rapid progress in the past two or three decades due to the increasing objective demands and the continuous infiltration of related technologies (such as computer science, immunology technology, molecular biology technology, etc.). Now, it is very obvious that there is a trend of "polarization", namely automation and simplification.

"▷ Automation

To eliminate errors in manual operation, enhance work efficiency and reduce personnel costs, manual operations in laboratories are gradually being replaced by automated machines. From flame photometers, automated blood cell counters, and multi-channel chemical analyzers in the 1950s to fully automatic biochemical analyzers in the 1970s and automatic immunoanalyzers in the 1990s; Now, we have entered the third generation of development - the automatic laboratory system, which connects several automatic devices to form a modular workcell. A further step is to connect all the processes before, during and after the analysis in a series of full laboratory automation (TLA).

"Simplification.

After traditional testing was automated, significant progress was made in both quality and speed. However, due to the numerous complex steps before and after analysis, which consume a considerable amount of time, it is still difficult to address the weakness of traditional testing - poor effectiveness, and it is hard to meet the clinical requirement of "obtaining accurate test results in the shortest time". That is, it is necessary to provide a short turn around time (STAT) feedback, and at the same time be consistent with the results determined by traditional methods that apply complex technologies and large-scale equipment. POCT is a brand-new experimental technology that provides accurate test reports in a timely and rapid manner with portable devices, simple operation and any location.

With the gradual deepening and continuous improvement of the market economy system, substantive progress has been made in the reform of the health system. Of course, various contradictions and problems are inevitable in the process of reform. Among them, the excessive growth trend of medical expenses has drawn widespread attention from society. How to rationally develop and utilize the existing medical and health resources under the premise of meeting social needs and maintain a reasonable growth rate of medical expenses is the current focus of research in the health industry. According to the investigation by relevant departments, the most resource-consuming item is the cost of medicines, with per capita medicine expenses accounting for over 50% of the total per capita expenses, followed by treatment expenses, which account for more than 25%. The factors influencing hospitalization expenses mainly include the length of hospital stay, the quality of diagnosis and treatment, and rational drug use in clinical practice. Shortening the test turn around time (TAT) is an important factor affecting the length of hospital stay. Timely and accurate test results are the guarantee for improving the quality of diagnosis and treatment. Providing individualized diagnosis based on the specific conditions of each patient is the prerequisite for rational clinical drug use, and POCT is entirely possible to be an effective way to achieve these goals.

Emergency medicine is also patient-centered, but its focus is on the patient's life. It uses the most advanced facilities and methods to save the lives of critically ill patients and minimize their disabilities to the greatest extent possible at the fastest speed and with the most effective means. This requires that the test results reflecting the vital signs of patients can be quickly and accurately fed back to the doctors, helping them make accurate and timely diagnoses and winning sufficient time for the final successful treatment.

Since the 20th century, with the wide application of technologies such as computer science, physics, mathematics, immunology, and molecular biology in the medical field, especially human genesThe successful completion of the group plan and the advent of the post-genetic era have led to the vigorous development of proteomics analysis technology, and breakthroughs have been made in molecular diagnostic technology. Simple, rapid, accurate and high-throughput detection has become possible. A small device, a simple piece of paper, and a one-centimeter-square chip can turn complex operations into simplicity, large devices into small ones, and reports that take several hours or even days into immediate results. Although it is simple and fast, the results are still correct. This is the advantage of POCT. There is a huge technological content here! It is precisely this huge technological content that nurtures a vast development prospect. Just like information technology, we can fully say that POCT is a microcosm of testing high-tech.