Interpretation
Interpretation of Metabolic Profiling Results
The final step of the metabolic profiling process is to integrate test interpretations with other clinical assessments to direct the decision making process to guide proactive nutritional, management, or environmental change to the current situation. Characterizing interpretation parameters to obtain valid information is the true challenge to metabolic profile testing.
The Need for Reference Ranges
A functional understanding of underlying metabolic and physiologic mechanisms controlling blood metabolite concentrations is necessary to properly interpret metabolic profiles and their application. One must appreciate the fundamental philosophic difference in blood analyte concentration interpretation between disease diagnosis and metabolic profiling paradigms. Disease diagnosis is focused on identifying critical outliers when compared to the population as a whole (i.e., 95% reference range). By definition, individuals sampled for metabolic profiling are expected to be within the 95% reference range for the population as they are "clinically normal". However, "normal" animals can be at risk for experiencing a disease if their metabolic status is trending away from the population central tendency. Blood analyte concentrations measure a continuous spectrum between health and disease and cannot be simply interpreted as "black or white". Metabolic profile criteria are more restrictive than the whole population and interpretation is based on statistical associations to disease risk. The single most important aspect of metabolic profiling is establishing valid reference values for comparison. (See Reference Values)
Caution! Same results, different causes?
It is very important for metabolic profile test results to be interpreted in light of animal, dietary, and environmental assessments. This point cannot be over-emphasized, metabolic profile testing results do not always indicate nutrition or diet to be the underlying problem. For example, inadequate dietary energy density is not the only reason for elevated NEFA concentrations. Inadequate dry matter intake as a results of heat stress, overcrowding, poor forage quality, competitive social interactions, inadequate feed availability or some combination of these could also account for observed negative energy balance. Results of metabolic profiling, depending upon the approach chosen, can provide disease diagnosis or insights into how to direct one's diagnostic investigation. The power of metabolic profiling comes from an ability to integrate multiple parameters to determine scope of metabolic aberrations present. Certain combinations of analyte alterations can provide insight into underlying disease pathogenesis and severity. Optimistically, protocols for disease mitigation and prevention can then be designed appropriately with some increased potential for success.
Reference:
Anderson, D. E. and Rings M. (2009) Current Veterinary Therapy: Food Animal Practice St. Louis, MO: Saunders Elsevier.
Interpreting Individual Samples
Pertinent Literature and Resources:
Use of metabolic profiles for the assessment of dietary adequacy in UK dairy herds. Macrae, A. I., D. A. Whitaker, et al. 2006. Vet Rec 159(20): 655-61.
The metabolic profile test: its practicability in assessing feeding management and periparturient diseases in high yielding commercial dairy herds. Kida, K. 2002 J Vet Med Sci 64(7): 557-63.
Metabolic profile in cows in the peripartum period with and without retained placenta. Kudlac, E., M. Sakour, et al. 1995. Vet Med (Praha) 40(7): 201-7.
Interpretation of pooled metabolic profiles for herd assessment. Davidek, J., Van Saun, R.J. Pp. 24, In: Oral and Poster Abstracts 25th Jubilee 25th World Buiatrics Congress, Budapest, Hungary, July 6-11, 2008.http://vetextension.psu.edu/resources/pdf/interpretation_czech.pdf
Interpretation of Pooled Metabolic Profiles for Evaluating Transition Cow Health Status (Poster)
Robert J. Van Saun, DVM, MS, PhD, Diplomate ACT and ACVN
Department of Veterinary Sciences, Pennsylvania State University
http://vetextension.psu.edu/Resources/pdf/pubs/rvs_pooled profile_WBC2006.pdf
Metabolic Profiling: Assessing Nutritional Status of the Transition Cow
Robert J. Van Saun, DVM, MS, PhD, Diplomate ACT and ACVN
Department of Veterinary Sciences, Pennsylvania State University
http://vetextension.psu.edu/resources/pdf/metabolic profiling trans.pdf
Blood Profiles as Indicators of Nutritional Status
Robery J. Van Saun, DVM, MS, PhD, Diplomate ACT and ACVN
Department of Veterinary Sciences, Pennsylvania State University
http://www.wcds.afns.ualberta.ca/Proceedings/2000/Chapter33.htm
Blood tests from individual animals are routinely used to diagnose disease problems in dairy cattle. Veterinarians, producers and nutrition consultants alike seem to be interested in extracting pertinent information relative to herd nutrition and health status from blood tests. The Compton Metabolic Profile (CMP) has traditionally been used in this approach (10). The original intent of the CMP was to: 1. monitor metabolic health of the herd; 2. help diagnose metabolic problems and production diseases, and 3. identify metabolically superior cows (10, 11). A "metabolic profile" is defined as a series of specific analytical tests run in combination and used as a diagnostic aid (7).
