CAP Manual Body Fluid Testing Guide

January 11, 2023

Manual body fluid testing is often overlooked with the adoption of automated systems. Streck recently reviewed the newest CAP critical updates concerning body fluid analysis inspection. Think like a CAP inspector to successfully navigate your next audit and provide the best possible patient care!

Manual Cell Count QC 

CAP requires laboratories to use appropriate QC for manual body fluid cell counts. Adequate QC for each 8-hour shift of patient testing includes:

  • A previously assayed patient sample, analyzed in duplicate
  • A procedural control used to encompass the entire analytical process
  • An assayed liquid control material

Evidence of Compliance: Policies and procedures for manual cell counting of body fluid samples and records of cell count or procedural control performed within the defined frequency.

Crystals

CAP requires that methods for evaluating body fluids be appropriate for the intended clinical use. For example, manually examining a synovial fluid may be clinically indicated for the observation of crystals.

Evidence of Compliance: Procedures that define the process for the identification of crystals, records of body fluid QC, and patient reports that show the presence of crystals.

WBC Differentials

CAP recommends using cytocentrifugation-type preparations, such as a cytospin centrifuge or similar concentrating system. These spun sample slides are then stained for better identification of different cell types.  The use of a procedural control to account for the entire testing procedure, such as centrifuging and staining, is ideal. The use of stained cytocentrifuge preps versus unstained is recommended.

Evidence of Compliance: Records showing the validation and use of cytocentrifuge for differentials.

Acceptable Limits for Automated Body Fluid Counts

CAP requires a protocol with documented limits and directions on how to proceed with counting body fluid samples when the reportable limits of the instrument are exceeded. There are automated system limitations for cell counting in very low cell concentrations which are typically published in instrument operator manuals.  For low cell concentration samples, use of a manual cell counting method may be required.

Evidence of Compliance: Procedure that documents the automated and semi-automated instruments limitations for cell counting in low concentrations and refers to a secondary counting method such as a manual cell count method. 

Morphological Observation Evaluation

CAP requires laboratories ensure the identification of body fluid cells are reported consistently among all personnel performing test. There are several methods for determining the consistency of manual techniques, including:

  • Former CAP survey photomicrographs
  • Previously graded smears
  • Multi-headed microscopy
  • Digital Images
  • Enrollment and participation of all personnel in an external assessment program

Evidence of Compliance: Records of evaluation, corrective action for discrepancies, and/or records of enrollment/participation in an external assessment program for all staff that perform body fluid analysis.  

Think like an inspector!

Successfully navigate your next audit and provide the best possible patient care!

Download the guide

Keep Cell-Chex® on hand for your manual body fluids testing!

Cell-Chex is a multi-level manual cerebrospinal and body fluid control for RBC and WBC counts. It is the only body fluid control assayed for the 5-part WBC differential and the only manual body fluid control that contains crystals to aid in crystal identification in synovial fluid samples.
Learn more about Cell-Chex here.

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