Ensuring the accuracy of laboratory test results through quality control has become a widely accepted principle both domestically and internationally. Modern laboratory medicine management advocates dividing quality control into three phases: pre-analytical, analytical, and post-analytical. Quality Control Before Analysis Because numerous departments are involved, such errors are difficult to control. Pre-analytical errors often stem from improper specimen collection, storage, and transport. Consequently, pre-analytical quality control directly impacts the accuracy of bacterial culture and antimicrobial susceptibility test results; therefore, it is essential to prioritize pre-analytical quality. Very important 。

Analysis of the Causes of Microbiological Nonconformity in Specimens:

In domestic microbiology laboratories, Phlegm and Urine The largest number of items were involved, and the nonconformities were the most serious.

The main reasons for unsatisfactory sputum samples are as follows:

( 1 ) Factors related to healthcare personnel: Since sputum collection for most patients requires their active cooperation, and many older patients are unsure how to properly collect a sputum sample, clinical nurses are typically tasked with arranging face-to-face supervision during the sampling process. In practice, however, staffing shortages in nursing units often prevent such in-person guidance from being provided.

( 2 ) Patient-related factors: Nursing staff may provide inadequate education, or some newly hired nurses themselves may lack a clear understanding of the importance of proper sputum specimen collection, allowing patients to collect samples arbitrarily. Alternatively, patients with limited educational backgrounds may fail to grasp the correct techniques for specimen collection, necessitating face-to-face instruction by nursing staff to guide them through the process.

( 3 ) Host factors: During sputum collection, the specimen is easily contaminated by oropharyngeal bacteria, which can compromise the accuracy of the culture. Therefore, minimizing contamination from oropharyngeal flora is critical for obtaining reliable results in sputum cultures.

The main reasons for unsatisfactory urine specimens are as follows:

(1) Common causes of contamination in urine cultures include improper use of the collection container,

(2) Contamination occurred during urine collection due to inadequate perineal cleansing, and some staff members lacked aseptic awareness, failing to maintain the required sterility of the collection container.

(3) The container was chosen incorrectly.

These situations frequently occur among newly arrived interns and trainees, often due to staff members failing to carefully read the specimen‑collection manual or lacking a strong sense of responsibility, resulting in inadequate instructions being provided to those involved.

How should we respond?

( 1 ) Establish pre-analytical quality control and foster close communication between patients and healthcare professionals.

Microbial sampling imposes stringent requirements on the timing, site, and method of specimen collection, as well as on the transport and preservation of samples; therefore, each step must be carefully managed, necessitating the establishment of a pre-analytical quality control system.

( 2 ) Conduct training through multiple approaches to enhance the knowledge and skills of healthcare professionals.

Training is a crucial means of ensuring that physicians and nurses perform procedures in accordance with quality standards. The laboratory staff have developed a clinical specimen‑collection manual, which they disseminate to clinical healthcare personnel in both print and electronic formats to facilitate learning and reference. This helps promote a meticulous and conscientious approach to the handling and processing of every clinical specimen. For certain common issues, the staff also produce concise informational cards—such as “Microbiological Testing Guidelines”—and distribute them to healthcare providers.

( 3 ) Optimize the specimen processing workflow

Bacterial culture specimens must be submitted for testing promptly. To ensure timely submission, the laboratory’s… The LIS system is integrated with the hospital’s HIS system to enable real-time specimen monitoring.

( 4 ) Close clinical communication

Strengthening clinical communication is an effective strategy for reducing the number of substandard specimens in microbiological testing. During specimen evaluation and acceptance, substandard samples should be promptly reported back to the clinical team, and joint analysis with healthcare professionals should be conducted to provide appropriate guidance on specimen collection, storage, and transport. For key departments, laboratory staff should collaborate with department heads and head nurses to identify underlying causes, develop corrective measures, and enhance clinical departments’ attention to proper specimen collection practices.

To ensure robust pre-analytical quality control in microbiological testing, it is essential to gain a comprehensive understanding of the causes and stages that give rise to pre-analytical errors, thereby reducing the number of unacceptable specimens and collectively advancing the overall quality of clinical microbiological testing.