A Closer Look At Advances In Functional Lab Testing

Author(s): 
By John E. Hahn, DPM, ND

   The modern podiatric physician is faced with many challenges when it comes to appropriate patient selection for surgical procedures. Specifically, when it comes to the high-risk patient with diabetes, there are potential challenges that can lead to postoperative complications and potential lawsuits. Indeed, some of these high-risk patients may experience delayed wound healing with no obvious preoperative disease elucidated in the preoperative history, physical and conventional laboratory studies.    Faced with these challenges, the astute podiatric physician now has the ability to order functional laboratory testing that will help ascertain a patient’s ability to heal postoperatively and reduce the incidence of postoperative infections. Accordingly, let us take a closer look at some of the most reliable functional tests available to podiatric physicians that can aid them in assessing potential risks of patients who have compromised health.

Understanding The Potential Impact Of Hypercortisolemia

   In our fast-paced society, many Americans are subjected to chronic stress, which influences the body’s ability to produce a normal circadian rhythm of cortisol from the adrenal glands.    Cortisol is a very powerful intrinsic hormone (see “Inside Insights On Cortisol Production” below) and can function as a catabolic hormone. For example, when blood sugar is low, cortisol stimulates the breakdown of protein and fat to produce glucose to counteract the low blood sugar. Cortisol is also important in moderating inflammation. Inflammation can result in greater damage to tissues than the original trauma that caused the inflammation. The adrenal glands increase cortisol production to control the inflammatory response. Cortisol also takes part in the regulation of blood volume and blood pressure by reducing the loss of sodium in the urine. Cortisol also helps to maintain emotional stability.    All of these cortisol effects assist the body in dealing with physical and emotional trauma and stress. Increased adrenal stress may also occur among patients who are undergoing operative procedures. There is the emotional stress of the contemplated surgical procedure. There is also the physical stress of the anesthetic and the surgical stress of tissue insult to both soft tissue and bone.    Chronically elevated cortisol, as the result of the aforementioned stressors, has many detrimental effects on the body. Hypercortisolemia causes increased protein breakdown and decreased protein synthesis. This effect can result in loss of muscle mass. A decrease in protein synthesis will also result in accelerated aging of the skin. Protein synthesis is essential for adequate soft tissue and postoperative bone healing.    Excess cortisol promotes osteoporosis by enhancing the breakdown of the protein matrix, which retains minerals in the bone and reduces the synthesis of the protein matrix for the formation of new bone. Accordingly, hypercortisolemia results in delayed bone healing for procedures involving osteotomies. Hypercortisolemia may also delay bone healing in fracture repair due to the aforementioned breakdown of protein matrix.    Hypercortisolemia will also reduce the uptake and utilization of intracellular glucose. This reduction has a significant effect on brain function since intracellular glucose is the optimum fuel for the cells of the brain and nervous systems.    Hypercortisolemia has a profound effect on the body’s immune system as it increases the body’s susceptibility to cancer cell growth. The increased protein breakdown secondary to hypercortisolemia and the decreased protein synthesis results in a decrease in lymph tissue with corresponding reductions in T cells and antibodies. There is also a dramatic reduction in production of secretory IgA in the presence of hypercortisolemia. This reduction increases the risks of bacterial and viral infections involving the respiratory, gastrointestinal, urinary and reproductive tracts. A low preoperative level of secretory IgA could increase the risk of a postoperative infection. Indeed, infectious agents disseminated from a site distant to the operative site could result in a postoperative infection.    Hypercortisolemia causes a reduction in the detoxification function of the liver as well as the body’s ability to chelate or remove heavy metals such as mercury. Patients undergoing surgery need to have optimal liver detoxification pathways available postoperatively. There needs to be detoxification in the liver from the anesthetics, analgesics and cellular debris that are created during the perioperative period.    Hypercortisolemia has a significant effect on the thyroid hormones and will result in a decrease in the active hormone T3 and increase the level of the inactive thyroid hormone rT3. Adults do not utilize rT3 in governing cell metabolism. Hypercortisolemia downregulates the production of 5-deiodinase. This enzyme is responsible for the conversion of T4 to T3 by the removal of any iodine molecule. Standard thyroid blood tests do not distinguish between active and inactive hormones. Thyroid hormone production is regulated by the pituitary hormone TSH (thyroid stimulating hormone). Persistent hypercortisolemia also reduces TSH production, thereby reducing the production of thyroid hormone at the same time in which the active thyroid hormone is already reduced.    This overall reduction in thyroid production and the conversion of T4 to the active T3 form has a negative impact on wound healing since it downregulates cellular metabolism. This reduction in cellular metabolism also affects the basal metabolic rate and impacts tissues that have been operated on, leading to delayed healing and/or a reduced rate of healing of both soft tissue and bone. The activities of the immunocytes are also directly affected by a decrease in thyroid hormone production. Accordingly, there is a reduced number of available antibody agents to fight infection.

Inside Insights On Cortisol Production

   Cortisol production by the adrenal glands follows a circadian rhythm. Levels of cortisol vary depending upon the time of day. Therefore, a dexamethasone suppression test would not give valid information to the clinician regarding the status of the cortisol output over a 12-hour period but only within a window of time in the morning.    Cortisol levels reach a peak between 7 to 8 a.m., and then gradually decrease to a low level around midnight. High cortisol levels at night, when adrenal production should be low, can result in insomnia and poor sleep quality. A nighttime peaking of the growth hormone is required to initiate quality rapid eye movement (REM) sleep. When cortisol is high, there is a reduction in the growth hormone and patients do not achieve REM sleep.    Conversely, low cortisol in the morning, when the cortisol level should be at its peak, can result in patients feeling tired and groggy when they wake up. Patients who think they need a caffeine boost in the morning may have a low cortisol output in the morning and a secondary functional hypothyroidism caused by the abnormal circadian rhythm of the adrenal/pituitary/thyroid axis.    There are many stressors that can lead to increased cortisol production. As noted earlier, these stressors may be physical, mental or emotional. When considering a patient for surgical procedures, one should strive to obtain a detailed assessment of a patient’s life stressors in the preoperative history in order to determine if a laboratory study of the patient’s cortisol output is necessary. What is the most common stressor that causes elevations of cortisol levels? Low blood sugar. The most common causes of low blood sugar are going too long between meals, meals with insufficient carbohydrates, meals and snacks with excess carbohydrates that result in a hyperinsulinemia response.    Chronic production of excess cortisol has also been noted in response to the physical stress caused by chronic pain and inflammation, as well as the stress introduced by excessive exercise and physical training. To minimize hypercortisolemia production, one should design a training schedule to give the body rest and healing times between workouts. Another stimulus of excess cortisol and abnormal cortisol rhythms is working the night shift or graveyard shift several days per week and then trying to be a “day person” on days off.    For women who use topical progesterone cream for even one month, it can cause an elevation in active cortisol levels if they absorb more of the progesterone hormone from the cream than what the body can break down each day (about 25 mg per day).    Stimulation of excess cortisol can also be caused by ingesting stimulants such as caffeine, guarine, ephedra and gotu kola. Decongestants such as Sudafed and adrenal gland extracts will also increase cortisol production.

Why Saliva Tests Are The Best Way To Measure Cortisol Output

   The most reliable functional laboratory test a podiatric physician can order to measure cortisol output is a saliva test. The World Health Organization has determined that these noninvasive saliva tests on certain hormones are much more accurate than serum levels. Salivary cortisol is measured at two or four different times during the day in order to evaluate the amount of free cortisol secreted by the adrenals and assess the rhythm of the cortisol secretion.    One may also measure cortisol in the blood and urine but these measurements have drawbacks. Whereas a saliva test measures only the active hormone, a blood test measures the total hormone, both bound and unbound. Accordingly, blood testing does not distinguish between active and inactive cortisol. Urine testing of cortisol only measures the active cortisol. However, urine cortisol is measured on all the urine collected during a 24-hour period. This test cannot tell if there are highs or lows in the cortisol levels at various times throughout the day. The time of day when active cortisol levels are high or low will indicate the cause of elevations and assist the practitioner in correcting abnormally high or low levels.    Many laboratories that offer salivary testing for cortisol levels also include levels of dehydroepiandrosterone (DHEA). Dehydroepiandrosterone is another hormone secreted by the adrenal glands and a building block for 17 other hormones essential for physical and emotional well-being.    Adrenal stress testing with saliva tests can also measure secretory IgA levels, which allows the podiatrists to know the level of resistance to disease the patient’s immune system will offer if it is exposed to pathogens. This is a very valuable piece of laboratory information for podiatric surgeons, who may be operating on patients with questionable immune functions from a past history of postoperative infections or infections in general. A low secretory IgA level can identify patients who are susceptible to both viral and bacterial infections.    Several laboratories in the United States supply practitioners with adrenal stress testing kits with return mailers at no charge to the physician. The patient takes this test kit home and provides the required four salivary samples at specific times during the day that are specified in the laboratory instructions. The patient then sends the completed sample back to the laboratory for analysis and the practitioner receives a printed or faxed report. The report usually presents several scenarios as to why the cortisol levels may be high or low. The report may also offer recommendations for further functional testing, such as a glucose tolerance test, if one suspects hypoglycemia or hyperinsulinemia.    The laboratories that I utilize in my practice for testing salivary cortisol levels are Genova Diagnostics and Diagnos-Techs Research Laboratory. Diagnos-Techs laboratory was the first laboratory in the U.S. to utilize precise hormone assays in salivary testing and offers clinical recommendations to the practitioner when it finds abnormalities.

Assessing The Benefits Of The Fasting Insulin Blood Spot Test

   The fasting insulin blood spot test is a new and unique functional test to determine if the patient’s abnormal cortisol levels are a result of abnormal sugar metabolism. This is a minimally invasive finger prick test and a few drops of blood are all that are needed to quantify fasting insulin levels.    This test offers particular insight into imbalances in people who have symptoms despite a normal blood glucose test or in individual patients who have known/suspected hypoglycemia, insulin resistance, diabetes, prediabetes or a family history of diabetes. One may also detect hyperinsulinemia among individuals who have longstanding obesity.    Low cortisol output in these particular patients is also of concern to the podiatric physician because low adrenal function can cause other symptoms such as pain and fatigue, recurrent infections, crashing during stress, hypoglycemia, low blood pressure and dizziness upon first standing.    The standard blood tests for cortisol functions may give faulty results as to the actual function of the adrenal gland output during the day. The normal range for a morning cortisol is 6 to 24 µg per deciliter. This range was actually based on an assessment of when one should consider cortisol deficiency a problem and the officially low cortisol probably occurs in less than one out of 100,000 people. Most healthy people have a morning cortisol level between 18 and 24 µg per deciliter. Nonetheless, a level of 12, 8 and even 6 is considered by most endocrinologists as totally normal and healthy. A level of 5.9 is considered life-threatening while a level of 6.1 is totally healthy.    What makes this concept scary is that the machine that analyzes the serum cortisol is only accurate within two points. Patients do not go from totally healthy to near death, based on a point 0.1 µg per deciliter difference in cortisol levels. However, this is how almost all endocrinologists in the United States practice reading these levels so it is not so surprising that they can miss most cases of inadequate/suboptimal adrenal function that is not life-threatening.

The Three-Hour Glucose Tolerance Test: Can It Help Assess Surgical Risks?

   In my clinical practice, I have found that a three-hour glucose tolerance test with a corresponding insulin level is very helpful in determining whether a patient may be a surgical risk because of hyperglycemia, hyperinsulinemia and insulin resistance when the patient is put under the stress of a 75g load of glucose after a 12-hour fast.    Patients who have a history of hypoglycemia — which they may have described in their history as becoming shaky and nervous, and then dizzy, irritable and fatigued when they get hungry — may be hypoglycemic with hyperinsulinemia. Many patients would have a normal fasting or two hour postprandial blood glucose. When challenged with a 75g load of glucose after a 12-hour fast, these people may have a normal blood sugar curve over the three-hour, four-draw blood test.    However, if the insulin levels are double to triple their normal range during the three-hour test, this may indicate insulin resistance and a possible prediabetic state. Patients who are scheduled for afternoon surgery may become hypoglycemic if they are NPO midnight and are scheduled for a general anesthetic. If the patient’s three-hour glucose tolerance test demonstrates high insulin levels or low blood sugars, these results will alert the podiatrist to plan accordingly and order the IVs to prevent a hypoglycemic reaction in that patient pre- or postoperatively.

Pertinent Pointers On Obtaining An Amino Acid Analysis

   It is important for the podiatrist to know how the patient’s protein metabolism will affect wound healing. In a recent study on the role homocysteine plays in wound healing, Boykin and Baylis determined that the amino acid homocysteine is a risk factor for impaired wound healing in 12 patients who were receiving a topical human fibroblast-derived dermal substitute treatment for non-healing lower extremity wounds.1 Researchers have shown that homocysteine is a significant risk factor for atherosclerotic vascular disease and it is an inhibitor of nitric oxide bioactivity.    The data from this preliminary study documented a correlation between elevated serum homocysteine and decreased levels of nitric oxide bioavailability in the wound, which impaired wound healing.1 Clinicians can correct elevated homocysteine by prescribing a combination product containing L-methylfolate, Pyridoxyl 5’-phosphate and methylcobalamin (Metanx, PamLab). This product increases the production of nitric oxide (NO) and facilitates normal wound healing in diabetic patients with chronic lower extremity ulcers.    One may analyze amino acids with a simple blood test or via a more comprehensive amino acid profile that would help determine intracellular amino acid deficiencies. Metametrix Laboratory performs functional amino acid analysis to determine intracellular levels of specific amino acids that are essential for wound healing. Doctors Data Inc. utilizes urine and plasma amino acid analysis, which provides fundamental information about nutrient adequacy. This analysis would enable one to gauge the quality and quantity of dietary protein, the presence of digestive disorders, and vitamin and mineral deficiencies, particularly folic acid, B12, B6 metabolism, zinc and magnesium.    In addition, amino acid analysis provides important diagnostic information about hepatic and renal function, the availability of precursors of neurotransmitters, detoxification capacity, susceptibility to occlusive arterial disease involving homocysteine, and many inherited disorders in amino acid metabolism. Any standard clinical laboratory is able to run serum homocysteine levels.    However, other actual intracellular amino acid levels that are essential for proper cellular function can be measured in a specific functional blood test provided by Metametrix Laboratory. In my own family practice, I have found that patients with attention deficit disorder (ADD) may have amino acid adsorption abnormalities. When these abnormalities are corrected by a specific targeted free-form amino acid oral supplement, the patients demonstrate clinical improvement.

Other Functional Tests For Evaluating Immunocompromised Patients

   Functional tests are available that will help evaluate the patient’s immune defense and repair the system in a way that would allow diagnostically predictive and therapeutic outcome monitoring.    Laboratory tests that lead to specific clinical actions or those that monitor specific outcomes during treatment qualify as functional tests. Conventional laboratory testing has been well reviewed in the literature but these tests have their limits when it comes to uncovering disease processes that are better elucidated by a functional test.    In the human body, the immune competence cells are divided between dendritic and lymphocytic cells. Dendritic cells include macrophages and monocytes, granulocytes and fibroblasts, endothelial cells and Kupfer cells in the liver, glial cells and sinusoidal cells in the spleen. The dendritic cells are the engulfers and recyclers in the body. Dendritic cells prevent us from developing an infection when they are robust and functional.    Defense and repair cells originally come from our bone marrow and mature in the thymus, spleen and lymph glands, particularly along the Peyer’s patches in the intestinal lining.    The different cell lineages that develop all share one common objective: to identify and destroy all substances, living or inert, that are recognized as not being part of what our body knows as “itself.” The cell lineages are therefore tolerant and nonreactive toward the body, which gives these cell lineages life.    When we are in good health, homeostasis is active within our bodies. This means our bodies can neutralize any foreign invaders while keeping up daily repair needs that the body requires. These repair needs are based upon wear and tear from normal daily life activities and surgical interventions. This means we can also return to equilibrium at the end of the day during our time of REM sleep. The role of a healthy immune system is to repair and keep the body resilient, flexible and resistant to disease.    Functional laboratory tests that measure different aspects of homeostasis and immune competency include the following tests:    Sedimentation rate and C-reactive protein (Hs CRP). These are available at a standard clinical laboratory.    Ascorbate calibration. This measures antioxidant need and turnover in the body.    Homocysteine levels. These levels measure methylation, a key to detoxification and repairs. This correlates with hypersegmentation of polymorphonuclear cells. One may obtain this blood test through the local reference laboratory.    Mercapturate and glucarate. These tests measure detoxification pathways through metabolites in urine. I utilize this test by sending my sample to Doctors Data Inc. This particular laboratory can also measure toxic heavy elements from hair and also in a 24-hour urine specimen. If the podiatric history elucidates a previous exposure to toxic metals, then this particular laboratory test is very useful to help determine the patient’s body burden and immune load.    Isoprostane. This measures antioxidant sufficiency.    Fasting glucose/insulin ratio. This assesses cell energetics, hypoglycemia and hyperinsulinemia. This test is available through the local hospital laboratory or in a freestanding clinical laboratory facility that will monitor the patient for extreme drops in blood sugar that could cause the patient to become disoriented and unable to drive home from the laboratory or hospital.    Creatine kinase with isoenzymes. This distinguishes skeletal muscle from cardiac muscle if the values are above the normal reference ranges in a screening blood test. One may order this blood test from the local clinical laboratory.    Blood urea nitrogen/creatinine ratio. This is also available through a local clinical laboratory.

Key Insights On Testing For Nutritional Status

   Health, nutrition and diets are major topics. In 2004, the Centers for Disease Control and Prevention stated that the major causes of death in the U.S. are chronic diseases such as cardiovascular and cerebrovascular diseases, cancer, diabetes, infections and immune system failures, making up more than two-thirds of all the deaths in this country.2    Obesity and malnutrition both play important roles in these mortality statistics. Within the last five years, over 17,000 articles have been published in medical journals on vitamin, mineral and or antioxidant deficiencies to hypertension and cardiovascular disease, cancer, diabetes and immune system disorders.    These articles provide strong evidence that suggests many of these illnesses possess a nutritional component and that correcting the nutritional issues may help ameliorate the severity of these often lethal illnesses. Vitamins are necessary for the treatment and prevention of chronic diseases in adults.3    How do we know if our patients are getting adequate vitamins and minerals from their standard American diets?    Shive developed a new functional test at Austin’s Biochemical Institute at the University of Texas. Shive realized that effective utilization of nutrition in medical practice depends upon the development of methods for assessing the nutritional status in each individual and identifying factors that limit the nutritional responses of each individual patient. Shive wanted to develop a comprehensive assay that took into account all factors affecting nutritional status (genetic and individual biochemistry, diet and the effect of environmental and physical stressors). The researcher also wanted to evaluate the cumulative effect of diet over a larger period of time than just a few days.4    Current nutritional assays measure serum levels of a given nutrient and they only represent a snapshot of the last few days and nutritional intake. Serum measurements also failed to take into account individual differences between the abilities of a person’s cells to take in nutrients and convert them into an active form for proper utilization by the body. Shive developed a functional method of intercellular nutrient analysis that has been performed commercially for approximately 11 years.    The idea of the functional intercellular analysis at its most basic is that by growing individual cells in a solution that lacks a specific nutrient, the cells are forced to rely upon their own stored supplies of that nutrient to grow and divide. By measuring the nutrient deprived cell growth in comparison to cells growing in a complete solution that contains all nutrients required for growth, one can functionally determine the nutritional status of a person.    If a person’s cells cannot mobilize a particular nutrient, whether for genetic, biochemical, dietary or other reasons, this test will identify that deficiency. Intracellular stores of nutrients accumulate over a period of months so this intracellular analysis may represent a more complete picture of overall nutritional status than other assays. Nutrients analyzed by this method are essential for cell growth and for the production of antibodies essential for prevention of infection.    This test is important to podiatric surgeons who are concerned about the nutritional status of patients who may have concomitant diseases such as diabetes and/or ulcerative colitis, and may have subclinical nutrient deficiencies that would affect their surgical outcome. Spectracell Laboratories offers such testing.

A Guide To Diagnostic Laboratories

   In regard to the laboratories mentioned in this article, one may contact them at the following numbers: Genova Diagnostics: (800) 522-4762 Diagnos-Techs Research Laboratory: (800) 878-3787 Metametrix Laboratory: (800) 221-4640 Doctors Data, Inc.: (800) 323-2784 Spectracell Laboratories: (800) 227-5227

In Summary

   Podiatric physicians and surgeons now have a host of clinically applicable functional laboratory testing procedures in their armamentarium to help assess the overall health of their patients and operative risks associated with metabolic diseases and or nutrient deficiencies that would compromise wound and bone healing. An added benefit in performing these tests would be the ability to refer these patients back to their primary care physician for further evaluation and treatment for previously undiagnosed conditions that one may detect by performing these functional laboratory tests.    By performing these functional laboratory tests for patients, it will serve notice to the medical profession that podiatric physicians are more than competent to evaluate the health compromised patients both from a physical and laboratory perspective. Dr. Hahn is in private practice at Trinity Clinic in Bend, Ore. He is board-certified by the American Board of Podiatric Surgery and is a member of the American Association of Naturopathic Physicians.
 

 

References:

1. Boykin J, Baylis C. Homocysteine: a stealth mediator of impaired wound healing: a preliminary study. Wounds a Compendium of Clinical Research and Practice 18(4):101-113, April 2006.
2. http:/www.cdc.gov/nccdphp/burdenbook2004/section01/tables.htm.
3. Fletcher RH, Fairfield KM. Vitamins for chronic disease prevention in adults. J Am Med Assoc 287(23):3127-9, 2002.
4. Shive W, Pinkerton F, Humphries J, Johnson M, Hamilton W, Matthews K. Development of a chemically defined sermon and proteins free medium for growth of human peripheral lymphocytes. Proc Natl Acad Sci USA 83(1):9-13, 1986. Additional References
5. Russell Jaffee, MD, PhD, Immuno Laboratories.
6. Jonathan Stein, PhD, Spectracell Laboratories.
7. Tietz N, Clinical Guide to Laboratory Tests, 2nd edition, 1990.
8. Shamberger R. Laboratory testing for the alternative medical clinic. Townsend Letter for Doctors and Patients 270, 2006.
9. Tuan C, Abbasi, et. al. Usefulness of plasma glucose and insulin concentrations in identifying patients with insulin resistance. Am J Cardiol. 2003; 92:606-10.
10. Allard P, Delvin E, et. al. Distribution of fasting plasma insulin, free fatty acids, glucose concentrations in the homeostasis model assessment of insulin resistance, Clinical Chemistry 49(4):644-9, 2003.
11. McLaughlin T, Abbasi F, Reaven G, et. al. Differentiation between obesity and insulin resistance in the association with C-reactive protein. Circulation. 2002; 106:2908–12
12. Boykin JV, et. al. Treatment of Elevated Homocysteine to Restore Normal Wound Healing: A Possible Relationship Between Homocysteine, Nitric Oxide and Wound Repair. Advances in Skin and Wound Care. July/ August 2005; pp. 297-300.

 

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