What are the consequences of improper storage of renal function clinical diagnostic reagent assay kit

Renal function clinical diagnostic kits are commonly used biochemical testing products in the field of in vitro diagnosis. They are widely used in the clinical monitoring and evaluation of acute kidney injury, chronic kidney disease, hypertension, diabetes and other related diseases. Common test indicators include creatinine, urea, cystatin C, uric acid, etc. This type of kit usually contains multiple components such as active enzymes, substrate solutions, buffer solutions, calibrators and quality control products. Their biological activity and chemical stability are highly dependent on standardized storage conditions. Once improperly stored, it will directly affect the performance of the reagents, thereby interfering with the test results, causing experimental errors and clinical misjudgments.

Decreased reagent stability
The core components of the kit include enzyme reactants (such as creatinase, urease, uricase), immune antibodies (such as antibodies for cystatin C detection) and colorimetric substrates. Improper storage can cause these active substances to degrade, denature or precipitate. For example, enzyme activity decreases rapidly under high temperature conditions, especially under storage conditions above 30°C. Even short-term exposure may significantly reduce enzyme activity, thereby reducing the efficiency of the reagent reaction system, reducing sensitivity, and causing low test values. For immunoturbidimetric reagents, changes in the antigen-antibody structure will cause reduced binding force, inadequate turbidimetric reaction, and affect the quantitative linear range.

Failure of calibration and quality control system
The renal function test kit relies on standard products to establish a standard curve and evaluate the system stability through quality control products. Calibrators generally contain standard substances with different concentration gradients, and their chemical stability is affected by factors such as temperature, light, and humidity. Once the storage environment does not meet the specifications, such as repeated freezing and thawing, improper light protection measures, and long-term frequent temperature fluctuations, the standard concentration will deviate from the theoretical value and the standard curve will be abnormal. Quality control products may also drift due to decreased activity or microbial contamination, resulting in batch-to-batch control failures, frequent instrument alarms, increased risk of test interruption, and affecting the laboratory's quality control compliance.

Decreased accuracy of test results
Improper storage will affect the repeatability, precision, and accuracy of the test kit. For basic metabolite indicators such as creatinine, urea, and uric acid, their determination often relies on colorimetry or enzymatic methods, and the concentration, pH, buffering capacity, and reaction rate of the reagent components are closely related. If the reagent has pH drift, substrate degradation, or changes in enzyme kinetic parameters due to improper storage conditions, the test value will fluctuate and the result will deviate from the true level. In clinical practice, false negative or false positive reports may occur, which may mislead the judgment of the condition.

Component stratification or precipitation phenomenon
Some liquid reagents will undergo physical changes such as phase separation, component precipitation, and turbidity after frequent temperature changes or long-term storage. For example, if crystals precipitate in the substrate solution, it may cause uneven reactions after sample addition. Precipitation of the buffer will change the ionic strength of the system and affect the efficiency of the enzyme reaction. Stratification of antibody components in immunoreagents will cause a decrease in antigen binding ability and form insufficient detection signals. If the technician fails to detect such physical changes and still conducts the test, it will cause serious interference to the patient's test results.

Increased risk of microbial contamination
Storage environments with high humidity, poor sealing, or frequent unsealing operations may expose the reagents to the air, increasing the risk of invasion of microorganisms such as bacteria and molds. If certain liquid reagents (such as substrate solutions or buffer solutions) do not contain preservatives or have a weak preservative system, they are prone to microbial growth if not refrigerated after opening, resulting in reagent turbidity, pH changes, or damage to the reaction system. This not only affects the test results, but also poses the risk of instrument contamination and cross-contamination, creating additional management pressure on the laboratory.