Body Fluid Analysis: Are You Ready for Inspection?

 

A guide for Body Fluid validation is available from CLSI. C49 Analysis of Body Fluids in Clinical Chemistry should be reviewed, and you should review your laboratory's validations for possible weakness when a CAP inspector asks "Do you have any LDTs? or "Are you using any a applications off-label?", or just "Are you performing body fluid testing?" 

Using a spreadsheet here are the suggested validations from the CLSI document and a place for what we have done and place for my medical director to detail if we need additional validation.

I provide this for you, but with the caveat that it does not replace the need for you to obtain the CLSI document and review it yourself.  It will be well worth your effort.

Key Point	Current Processes	Follow Up Actions
Definitions of Fluids: Includes names of processes of removal (BF—centesis) Pericardial Peritoneal- aka Ascitic fluid Pleural
Proper instruction provided for collection and transport is provided to user; being part of validation for body fluid testing.
Laboratory needs to evaluate clinical requests and inform which tests will not be provided.
Pleural Fluid for pH should be collected and tested as blood gas sample.
Specimen processing: pretreatment, specimen viscosity issues and various techniques: dilution, freeze-thaw cycles, hyaluronidase.  These processes should be included in validation plan.
Measurement Procedure Selection based on expected measuring range need to consider appropriate analyzer application [and reagent choice].
Measurement Procedure Validation- Accuracy: comparative reference measurement, spiked studies, 40 samples.
Measurement Procedure Validation- Spiked Recovery: three specimens each spiked three times with comparison of observed vs. expected results.
Measurement Procedure Validation- Mixing Studies: 3 pair specimen sets.
Measurement Procedure Validation- Dilution Recovery: three specimens diluted at three different concentrations.
Measurement Procedure Validation- Precision: 2 specimens near medical decision points, 5 reps for 5 days.
Measurement Procedure Validation- Detection Capability: prepare four diluted samples using specimen that is above the LLoQ and blank sample.
Measurement Procedure Validation- Linearity, AMR: 7 – 9 samples prepared by mixing, spiking and dilution prepared to demonstrate linearity over the proposed measuring range.
Measurement Procedure Validation- Reference Interval and Medical Decision Limits: Laboratory should provide guidance in interpreting results even if intervals cannot be defined.
Measurement Procedure Validation- Endogenous Interference Testing: due to the possibility that manufacturer tested interferences may exist in higher concentrations in body fluids the laboratory should access if these studies are directly transferable and perform evaluations when appropriate.
Measurement Procedure Validation- Sample Processing: perform paired difference protocol on specimens for various sample processing techniques such as those to reduce sample viscosity.
Measurement Procedure Validation- Stability: laboratory should establish stability as it relates to body fluids as possibly different than blood samples.
Ongoing Quality Assurance- Quality Control Selection: Controls used for serum assays are usually sufficient, taking note that levels should be appropriate for expected values in body fluids if different.
Ongoing Quality Assurance- New Reagent Validation: inclusion of body fluids for correlation should be considered; however, if reagent is only used for body fluid then body fluids should be used.
Ongoing Quality Assurance- Biannual Instrument Measurement Comparisons: body fluid specimens should be included.
Ongoing Quality Assurance- Biannual Linearity and AMR Verification: commercially available martials for serum, plasma, urine are acceptable.
Ongoing Quality Assurance- External Quality Assessment: commercially available products for body fluids should be used.  When not available, but a serum/ urine is available then an alternate is not required.  When neither body fluid or serum/ urine is available then and alternate assessment is required.