Pretreatment of Body Fluid Specimens Using Hyaluronidase and Ultracentrifugation

A Review of Current Practices and Future Trends in Body Fluid Testing

BACKGROUND

Body fluid testing in the clinical chemistry laboratory is a cornerstone in the diagnostic workup of pathological effusions. Laboratorians may not be aware of the preanalytical workflows used in the collection of body fluids though the value is evident whenever processes change or issues arise. The analytical validation requirements can vary depending on the regulations dictated by the laboratories' jurisdiction and accreditor requirements. Much of analytical validation hinges on how useful testing is to clinical care. Usefulness of testing varies with how well established and incorporated the tests and interpretation are in practice guidelines.

CONTENT

Body fluid collections are depicted and described so clinical laboratorians have a basic appreciation of what specimens are submitted to the laboratory for testing. A review of validation requirements by major laboratory accreditation entities is presented. A review of the usefulness and proposed decision limits for common body fluid chemistry analytes is presented. Body fluid tests that show promise and those that are losing (or lost long ago) value are also reviewed.

SUMMARY

The total testing process from collection to result interpretation can be complicated and easily overlooked by the clinical laboratory. This review aims to improve the understanding and awareness of collections, validation, result interpretation, and provide an update on recent trends.

Evaluation of an Adenosine Deaminase (ADA) Assay in Serum, Pleural, Pericardial, Peritoneal, and Cerebrospinal Fluids on the Roche cobas c501 Analyzer

OBJECTIVES

Adenosine deaminase (ADA) can be increased in various body fluids during infectious and inflammatory states. The objective of this study was to evaluate the performance characteristics of the Diazyme ADA assay for serum, pleural, pericardial, peritoneal, and cerebrospinal fluids using the Roche cobas c501 analyzer.

METHODS

Accuracy, linearity, recovery, precision, sensitivity, specificity, reference interval, and stability studies were conducted. Potential interference of hyaluronidase and ultracentrifugation pre-treatment for viscosity on ADA concentrations were further evaluated.

RESULTS

Assay method comparison to two separate external laboratories showed the following results (slope, intercept, %bias): serum (1.053, -0.478, 4.4%); pleural (1.046, -1.41, 2.6%). Accuracy (109.6% recovery) was further demonstrated using a commercially available ADA reference material (BCR647). Linearity and spiked recovery studies showed percent recoveries ranging 94.3-109.3%. Precision across all specimen types was ≤4.7%CV. Interference was observed with increasing concentrations of various sources of conjugated and unconjugated bilirubin. Reference intervals were established for serum and pleural fluids, and previously published reference intervals were verified for pericardial, peritoneal, and cerebrospinal fluids. All specimen types were stable for 24 hours ambient (8-25°C), 1 week refrigerated (2-8°C), and 1 month frozen (-20°C). Of the two types of hyaluronidase evaluated, one showed positive interference for ADA (Sigma-Aldrich, H3506; 4.59 to 17.90 average % difference from baseline). Ultracentrifugation did not interfere with results (-2.32 to 0.87 average % difference from baseline).

CONCLUSIONS

The Diazyme ADA assay was validated for use in our laboratory for all fluid types evaluated. Interference was observed with increasing concentrations of bilirubin and one source of hyaluronidase.

Insights into the source, mechanism and biotechnological applications of hyaluronidases

It has long been found that hyaluronidases exist in a variety of organisms, playing their roles in various biological processes including infection, envenomation and metabolic regulation through degrading hyaluronan. However, exploiting them as a bioresource for specific applications had not been extensively studied until the latest decades. In recent years, new application scenarios have been developed, which extended the field of application, and emphasized the research value of hyaluronidase. This critical review comprehensively summarizes existing studies on hyaluronidase from different source, particularly in their structures, action patterns, and biological functions in human and mammals. Furthermore, we give in-depth insight into the resource mining and protein engineering process of hyaluronidase, as well as strategies for their high-level production, indicating that mixed strategies should be adopted to obtain well-performing hyaluronidase with efficiency. In addition, advances in application of hyaluronidase were summarized and discussed. Finally, prospects for future researches are proposed, highlighting the importance of further investigation into the characteristics of hyaluronidases, and the necessity of investigating their products for the development of their application value.