Introduction to Functional Lab Tests and Standardized Assessment Instruments
This section contains excerpts from Dr. Weyrich's notebook of naturopathic and functional diagnostic medicine. It represents a snapshot of Dr. Weyrich's ongoing studies in functional diagnostic medicine that may be of interest to patients and other medical professionals.
Functional Lab Tests (Overview)
Functional laboratory testing seeks to evaluate physiological function and metabolic efficiency rather than simply measuring the concentration of nutrients or other analytes in the blood. Whenever possible, these tests assess downstream metabolites or functional biomarkers (for example, Methylmalonic Acid as an indicator of intracellular vitamin B12 activity) that may reveal impaired biochemical function despite apparently normal serum nutrient concentrations.
Because metabolic pathways are influenced by genetics, nutrition, medications, disease states, environmental exposures, and other individual factors, functional biomarkers may identify clinically relevant metabolic disturbances that are not apparent from conventional concentration-based laboratory tests alone. Functional testing should therefore be interpreted as complementary to, rather than a replacement for, standard laboratory evaluation and clinical assessment.
Functional biomarkers provide insight into the dynamic performance of individual physiology and metabolic pathways, much as evaluating the output (airflow, cooling efficiency, energy consumption) of an HVAC system provides more information than measuring only the value of one input variable, such as the ambient temperature.
Standardized Assessment Instruments (Overview)
Standardized Assessment Instruments are paper-based or computerized questionnaires and rating scales designed to objectively assess symptoms, functional status, cognitive abilities, behavioral characteristics, or quality of life. They generally fall into two broad categories:
- Screening Tools identify or estimate the severity of conditions such as anxiety, depression, stress, autistic traits, ADHD symptoms, sleep disorders, or other clinical concerns that may warrant further evaluation.
- Outcome Measures are administered repeatedly over time to objectively monitor changes in symptoms, function, or quality of life, thereby helping to assess treatment response, guide clinical decision-making, and document patient progress.
Many instruments serve both purposes: they provide an initial baseline assessment and, when repeated at appropriate intervals, function as longitudinal outcome measures.
Laboratories Used by Dr. Weyrich
Beware that most labs have two prices - "cash" and "list" with the list price being substantially higher. If you ask the lab to bill insurance and the insurance pays less than the list price, then the lab may "balance bill" you for the remainder of the list price. It is safer to always pre-pay cash and then submit the receipt to insurance for reimbursement.