Laboratory testing of extravascular body fluids

Abstract

Extravascular body fluids (EBF) analysis can provide useful information in the differential diagnosis of conditions that caused their accumulation. Their unique nature and particular requirements accompanying EBF analysis need to be recognized in order to minimize possible negative implications on patient safety. This recommendation was prepared by the members of the Working group for extravascular body fluid samples (WG EBFS). It is designed to address the total testing process and clinical significance of tests used in EBF analysis. The recommendation begins with a chapter addressing validation of methods used in EBF analysis, and continues with specific recommendations for serous fluids analysis. It is organized in sections referring to the preanalytical, analytical and postanalytical phase with specific recommendations presented in boxes. Its main goal is to assist in the attainment of national harmonization of serous fluid analysis and ultimately improve patient safety and healthcare outcomes. This recommendation is intended to all laboratory professionals performing EBF analysis and healthcare professionals involved in EBF collection and processing. Cytological and microbiological evaluations of EBF are beyond the scope of this document.

Laboratory testing of extravascular body fluids: National recommendations on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine. Part II – Synovial fluid

“…cell count, differentials) and crystals diagnostics are feasible from a few drops of the SF sample. If a recommended sample volume is not available, the clinician should prioritize the test requested according to the suspected diagnosis in collaboration with the laboratory (which acknowledges the sufficiency of the sample volume for the requested tests) (7,19). Synovial fluid samples delivered to the laboratory for analysis in large syringes are generally not acceptable, especially regarding synovial fluid sample clotting (15).…”

“…Recommendations for method validation as well as quality control and proficiency testing in the EBF analysis are available in the first recommendation of the WG EBFS and should be applied in the SF analysis (7,15).…”

“…fat globules, cartilage fragments, crystals) which may cause pseudoleukocytosis or pseudoeosinophilia, and the presence of possible matrix effect which might affect proper sample aspiration. Therefore, unclear automated results, SF samples with low WBC count, suspected malignant samples, as well as suspected interferences should be verified by manual microscopy (3,5,7,8,13,40).…”

“…These results, combined with a thorough review and critical assessment of all available scientific evidence, were used to design this document. This recommendation is the second in the series of recommendations prepared by the members of the WG EBFS of the CSMBLM (7). It addresses the preanalytical, analytical, and postanalytical issues and clinical significance of tests used in SF analysis with the aim of improving the value of SF laboratory testing in the diagnosis of joint diseases and assisting in the achievement of national harmonization of SF testing.…”

“…Specific recommendations are presented in a box at the beginning of each section, followed by explanations and data derived from relevant literature. Similar to the first WG EBFS's recommendation dedicated to serous fluids laboratory testing, cytological and microbiological testing are beyond the scope of this document since they are not performed in Croatian medical biochemistry laboratories (7).…”