The analysis and description of field generated containment in fluid systems (hydraulic or lubricating oil, fuels, water, etc.) continues to be one of the best indicators of system “health.” The monitoring of the contaminant provides an effective health measure by accurate determination of the contributing factors to system degradation. These include solid particles, water, additive depletion, and a host of resultant synergistic effects such as sludges, gels, etc.Their are many options available for field fluid analysis. Five specific analyses have been found to provide an extensive description of field contaminants. They are particle counting, gravimetric level analysis, proton induced X-ray emission (PIXE) analysis, ferrographic wear debris analysis, and water content analysis. Thorough descriptions of this procedures is provided with detailed application considerations.This paper presents guidelines and suggestions for obtaining a true representation and understanding of field induced and generated contaminant in fluid systems. Many thousand samples performed for hundreds of engineering studies form the basis for this paper. Specific case studies and results are presented to aid in understanding and troubleshooting a system's health based upon its contaminant content and type, particle size distribution, and chemical composition.