The importance of quality control in laboratories

While no good laboratory ever sets out to make mistakes, it is impossible to plan for every eventuality. That’s why maintaining quality control in a laboratory setting is imperative. Not only does it help ensure the accuracy, reliability, and consistency of diagnostic test results but it also safeguards patient health.^1,2

So how exactly do you go about ensuring effective quality control in a lab-based environment? And how can you recognize which processes you need to hone and optimize to maximize the potential benefits that maintaining effective quality control can offer? Let’s take a closer look.

Quality control in the lab refers to all the healthcare measures that are put in place to identify and resolve issues with lab results.^1,2 It involves regularly incorporating systems that improve the accuracy, reliability, and timeliness of results, to ultimately support the overall goal of enhancing clinical decision-making.^1-3

Quality control procedures are critical to managing the overall quality of patient sample results and identifying any errors before they potentially impact patient care.³ This, in turn, helps to build trust among lab leaders, healthcare professionals, and patients alike.

One of the most essential aspects of laboratory operations is internal quality control (IQC). As defined by the World Health Organization, this involves using “a set of procedures to continuously assess laboratory work and the emergent results”.⁴ IQC differs from external quality control, which consists of using processes and materials to compare one laboratory against another.^5,6

IQC procedures employ statistical and non-statistical techniques to verify the overall quality of results, such as Levey-Jennings charts for data interpretation.^2,6 These processes also involve using control materials that resemble patient samples to verify test results and equipment performance.⁶ By comparing these control results to established standards, labs can detect — and act upon — any inconsistencies or errors more quickly, helping ensure the reliability of patient test results.² This is critical in helping to identify trends that may indicate potential quality issues, such as with testing reagents or equipment.²

For example, if a glucose quality control reagent was expected to produce results of 100 mg/dL on average, yet repeat results of the same reagent gave 96, 98, 101, 92, 93, 88, 92, 93, 91, 90, and 98 mg/dL, this would indicate a low bias result in the instrument.² Not running IQC tests to determine this information could lead to inaccurate readings being passed on to patients, resulting in less successful patient care.

A laboratory quality management system (LQMS) is defined by The International Organization for Standardization (ISO) and the Clinical and Laboratory Standards Institute (CLSI) as “coordinated activities to direct and control an organization about quality” in a way that investigates the entire laboratory system.⁷

Creating a strong LQMS framework should be centered around ensuring all aspects of laboratory operations meet quality standards and that all elements of quality control — including documentation, standard operating procedures (SOPs), and continuous improvement processes — are sufficiently integrated. It should also include all the managerial and technical aspects that are associated with lab procedures.¹

Since approximately 70 - 75% of all medical diagnoses are obtained via clinical lab reports, the quality of a lab’s service can directly impact the quality of healthcare provided.⁵ Therefore, each LQMS framework should strive to keep all laboratory processes controlled and consistent, emphasizing the importance of standardized procedures, staff training, and regular instrument audits.^5,8

Due to the nature of the clinical laboratory environment, there are various types of quality control to consider when ensuring the accuracy and reliability of test results. These need to be enforced at different stages of laboratory processes, including:¹

1. Pre-analytical stage — errors in the pre-analytical stage occur when test samples or materials are mishandled before being analyzed. These errors can include samples being mixed up, mislabeled, not stored properly, or being collected in an unsuitable way. To minimize these errors, it is important to follow proper sample collection procedures by ensuring clear labeling, correct transportation, and appropriate storage protocols are followed.
2. Analytical stage — errors during the analytical stage often arise due to using incorrect test reagents or quantities of reagents, defective equipment, or not complying with SOPs. To minimize these errors, it is important to correctly maintain and calibrate equipment, regularly update the reagent inventory, clearly document SOPs, and ensure staff are trained to comply with these procedures.
3. Post-analytical stage — errors in the post-analytical stage can include the incorrect calculation, recording, or interpretation of a patient’s result. As such, minimizing these errors can be achieved by avoiding manual calculations and ensuring only trained staff members are allowed to interpret and make appropriate recommendations based on the results.

Each type of quality control plays a crucial role in the overall accuracy and reliability of laboratory operations, helping to identify and correct errors at every stage of the testing process.

Want to find out more about successful quality management within the lab? Check out our article on strategies for successful quality management within the laboratory.

Failing to integrate quality control in a laboratory can result in severe negative consequences, including:¹

• Potential misdiagnoses or incorrect treatments being administered

• Treatment delays 

• Compromised patient safety

• Time wastage

• Budget implications

Errors in laboratory results can also damage a laboratory’s reputation, leading to a potential loss of trust amongst healthcare providers and patients. As such, ensuring rigorous quality control procedures is vital to help minimize these risks. 

Quality control in laboratories is crucial to ensuring the accuracy, reliability, and consistency of diagnostic tests.^1,2 By implementing robust internal and external quality control procedures and maintaining a comprehensive LQMS, laboratories can help safeguard patient safety, enhance diagnostic accuracy, and meet the ever-evolving demands of modern healthcare in the right way.²