Brief Description of Certain Panel Tests
1,25 Dihydroxy Vitamin D
1,25 Dihydoxy Vitamin D is the biologically active form of the vitamin obtained in the body by the metabolism of 25 Hydroxy Vitamin D. Its renal production is controlled by the Parathyroid Hormone and is important in the regulation of calcium homeostasis. This test is primarily indicated during patient evaluation for hypercalcemia and renal failure. A normal result does not rule out Vitamin D deficiency, which is diagnosed by testing for 25 Hydroxy Vitamin D.
Advanced Cardiovascular Panel
The Advanced Cardiovascular Panel expands the routine lipid panels comprising of Total HDL and LDL Cholesterol and Triglycerides, which are approximately 40% accurate in predicting the risk of heart attacks. The measurement of the LDL subtype Lp(a), when it is the predominant form of LDL, alerts against an increase in the risk of heart attack up to 25 times. On the other hand, measurement of the sub-types of HDL i.e. HDL1 and HDL2 give useful information about the protection against heart disease; higher levels of the latter being far superior to those of the former. Low levels of
Apolipoprotein A1 with high levels of Apoliproteoin B, as determined by the Apo B/Apo A1 ratio are an additional predictor of heart disease and help alert the physician to better manage potential heart disease patients.
Aldolase testing is helpful in the evaluation of muscle wasting disorders. Elevated levels are found in progressive Duchene Muscular Dystrophy (MD); in carriers of the disease; in limb girdle and other dystrophies; in Dermatomyositis, Polymyositis and Trichinosis, but not in Neurogenic Atrophies e.g. Multiple Sclerosis or in Myasthenia Gravis.
Increased levels of α1-antitrypsin may be helpful in the diagnosis of Rheumatoid Arthritis.
Anaplasma Phagocytophilum Antibodies
Anaplasma phagocytophilum is a bacterium which causes human Granulocytic Anaplasmosis, a multisystemic disease marked by anemia and Leucopenia in its most severe form. Other symptoms include fever, headache, skin rash, Thrombocytopenia, mild injury to the liver as well as lethargy, ataxia and weak or painful limbs. The disease was first identified in a Wisconsin patient who died with a severe febrile illness two weeks after a tick bite. During the last stage of the infection, a group of small bacteria were seen within the Neutrophils in the blood. This organism causes lameness and is often confused with Lyme Disease, the major tick-borne illness.
Anti-Cyclic Citrullinated Peptide (CCP)
Anti-Cyclic Citrullinated protein antibodies (ACPA) are auto-antibodies that are frequently detected in the blood of Rheumatoid Arthritis patients. In July 2010, the 2010 ACR/EULAR Rheumatoid Arthritis Classification Criteria were introduced. These new classification criteria include ACPA testing, overruling the ACR criteria of 1987 and are adapted for early RA diagnosis.
Antibodies to ds DNA are present in approximately 80- 90% of patients with Systemic Lupus Erythematosus (SLE), but their presence is not necessary or diagnostic of SLE, as they are present in smaller percentages of patients with other Rheumatoid Disorders and also in some non-Rheumatoid Disorders.
Anti-Nuclear Antibodies (ANA)
Anti-nuclear Antibodies target ‘normal’ proteins within the nucleus of a cell and could signal the body to begin attacking itself which can lead to autoimmune diseases, including Lupus, Scleroderma, Sjögren’s Syndrome, Polymyositis/Dermatomyositis, mixed connective tissue disease, drug-induced Lupus, and autoimmune Hepatitis. A positive ANA can also be seen in Juvenile Arthritis. A positive ANA test means that auto antibodies are present, but by itself does not indicate the presence of an autoimmune disease or the need for therapy.
Anti-Pancreatic Cell Antibodies
Islet cell antibodies (ICAs) are associated with Insulin Dependent Diabetes (IDDM). These antibodies may be present in individuals, years before the onset of clinical symptoms. Measurement of these antibodies is of use in differentiating Type I from Type II Diabetes.
Measurement of anti-RNP antibodies is of use in the diagnosis of SLE; 80% of the patients with SLE test positive for these antibodies.
Anti-SCL-70 antibodies are used to evaluate certain immune system disorders such as Systemic Sclerosis (Scleroderma) and SLE. The test may identify a subset of patients with severe skin and joint disease.
Anti-Smooth Muscle Antibodies
Anti-smooth muscle antibodies are formed against smooth muscle. These antibodies can be directed against Actin, Troponin, and Tropomyosin. These antibodies are typically associated with autoimmune Hepatitis.
The Thyroid gland produces a number of different proteins, including Thyroglobulin, which helps produce the hormones released by the Thyroid gland. When the body’s immune system attacks Thyroglobulin, a corresponding antibody, known as the anti- Thyroglobulin antibody is produced. A positive test for anti-Thyroglobulin antibodies may be caused by a number of primary Thyroid conditions such as Hashimoto’s Thyroiditis, Hypothyroidism, Grave’s Disease, Thyrotoxicosis, Myxedema or Thyroid Cancer. They can also be increased due to other diseases such as Diabetes or Systemic Lupus Erythematosus (SLE). Pregnancy can also lead to anti-Thyroglobulin antibodies being present in the blood.
Anti-Thyroid Peroxidase Antibodies (Anti-TPO)
Anti-Thyroid Peroxidase (anti-TPO) antibodies are specific to the Autoantigen TPO, that catalyses iodine oxidation and Thyroglobulin Tyrosyl Iodination reactions in the Thyroid Gland. Anti-TPO antibodies are the most common anti-Thyroid autoantibodies present in approximately 90% of Hashimoto’s Thyroiditis, 75% of Grave’s Disease and 10%-20% of nodular Goiter or Thyroid Carcinoma. Also, 10%-15% of normal individuals can have high level anti-TPO antibody titers. High serum antibodies are found in active phase chronic autoimmune Thyroiditis. Thus, an antibody titer can be used to assess disease activity in patients that have developed such antibodies.
Babesia Microti Antibodies
Babesiosis is another Tick-borne disease whose symptoms of fatigue, malaise, Myalgia, Arthralgia, chills and fever are similar to those of Lyme Disease. The disease is particularly life threatening in splenectomized patients. Although the presence of the bacterium can be detected in a blood smear, this may not be the case when the level of parasitemia is low. Presence of antibodies confirms infection.
C3, C4 Complement
Changes in the levels of C3 and C4 may be early warning signs of an inflammatory process in the body. Measurement of complement proteins can be used to monitor treatment results in patients with autoimmune diseases. Lupus Erythematosus can cause a C3 level below normal, while Rheumatoid Arthritis may cause it to rise in the blood but fall in the joint fluid.
Ceruloplasmin acts as an ‘acute phase reactant,’ although its levels change more slowly that other substances in this category. High levels are seen in SLE and Rheumatoid Arthritis, although not specific to these conditions.
Coenzyme Q10 (CoQ10) is produced by the human body and is necessary for the basic functioning of cells. CoQ10 levels are reported to decrease with age and to be low in patients with some chronic diseases such as heart conditions, Muscular Dystrophies, Parkinson’s Disease, cancer, Diabetes, and HIV/AIDS. Some prescription drugs may also lower CoQ10 levels.
Measurement of Cortisol, the ‘Stress’ hormone, is used as an aid in establishing the diagnosis of Adrenocortical insufficiency, Addison’s Disease, Adrenocortical Hyper- secretion and Cushing’s Syndrome. Cortisol levels are affected by malfunctioning of the organs in the Hypothalamic – Pituitary – Adrenal Cortex axis.
Creatine Kinase, MB
This test includes the performance of total Creatine Kinase, which is elevated in skeletal muscle damage and to rule out that the elevation is not due to damage to heart muscle, following chest pains.
Human Cytomegalovirus (HCMV) is found throughout all geographic locations and socioeconomic groups, and infects between 50% and 80% of adults in the United States, as indicated by the presence of antibodies in much of the general population. Seroprevalence is age- dependent: 58.9% of individuals aged 6 and older are infected with CMV while 90.8% of individuals aged 80 and older are positive for HCMV. A positive result indicates that the patient has the antibody to CMV. It does not differentiate between an active or past infection. The clinical diagnosis must be interpreted in conjunction with the clinical signs and symptoms of the patient. Results from any one IgM assay should not be used as a sole determinant of a current or recent infection. Because IgM tests can yield false positive results and low levels of IgM antibody may persist for more than 12 months post infection, reliance on a single test result could be misleading. The presence of CMV IgM suggests a recent CMV exposure, but does not differentiate between primary infection and reactivation, whereas a positive CMV, IgG antibodies test indicates a past infection. Testing for the presence of CMV Antibodies has been suggested to be of value in the assessment of Chronic Fatigue Syndrome.
DHEA-S is the most abundant steroidal hormone in the body produced exclusively by the adrenal glands and is therefore useful in the assessment of adrenal function, including Congenital Adrenal Hyperplasia (CAH) and adrenal tumors. Levels of DHEA-S are low in Addison’s Disease. Measurement of DHEA-S in females is of great help in the different diagnoses of infertility, Amenorrhea, hirsutism, virilization, all of Androgenization, and to rule out an Androgen Producing tumor of the adrenal cortex. DHEA-S measurements are useful for the evaluation of precocious puberty in males.
Ehrlichia Chaffeensis Antibodies
This test is used as an aid in the diagnosis of Human Monocytic Ehrlichiosis, a tick borne disease.
Epstein Barr Virus Antibodies
The Epstein–Barr virus (EBV), also called human Herpes Virus 4 (HHV-4) is one of the most common viruses in humans. It is the causative agent for Infectious Mononucleosis, but is also associated with particular forms of cancer, such as Hodgkin’s Lymphoma, Burkitt’s Lymphoma, Nasopharyngeal Carcinoma, and conditions associated with Human Immunodeficiency Virus (HIV), such as Hairy Leukoplakia and central nervous system lymphomas. There is evidence that infection with the virus is associated with a higher risk of certain autoimmune diseases, especially Dermatomyositis, SLE, Rheumatoid Arthritis, Sjögren’s Syndrome, and Multiple Sclerosis. Most people become infected with EBV and gain adaptive immunity. In the United States, about half of all five-year-old children and 90% to 95% of adults have evidence of previous infection. Infection with Epstein Barr Virus has been postulated to play a role in the pathogenesis of Chronic Fatigue Syndrome.
Estradiol is the primary sex hormone in non-pregnant females, but is also produced in small amounts by males. It plays an important role in normal fetal development and in the development of secondary sexual characteristics in females. Estradiol is responsible for the maturation and maintenance of the uterus during the normal menstrual cycle. Measurement of Estradiol levels in females are used for the evaluation of infertility and in the management of in-vitro fertilization. Elevated levels of Estradiol in men may result from increased body fat leading to enhanced peripheral aromatization of Androgens, as well as due to excessive use of Marijuana, alcohol or as a side effect of some prescription drugs including Phenothiazines and Spironolactone. Increased levels of Estradiol may cause Gynecomastia in males. Estradiol levels may be dramatically elevated in germ cell tumors and tumors of a number of glands in both men and women.
Most of the iron stored in the body is bound to the protein Ferritin, which is found in the liver, spleen, skeletal muscles, and bone marrow. Only a small amount of Ferritin is found in the blood. Measurement of Ferritin in the blood shows how much iron is stored in the patient’s body and is used to determine the cause of anemia, especially of iron deficiency, as well as to monitor treatment with Iron.
Fibrinogen is an acute phase reactant and can often become significantly elevated in conditions involving tissue damage or inflammation. Recent research has shown that Fibrin plays a key role in the inflammatory response and development of Rheumatoid Arthritis.
Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)
The Pituitary Gonadotropins, FSH and LH are found in elevated levels in Hypogonadism, Anorchia, gonadal failure, complete Testicular Feminization Syndrome, menopause, Klinefelter’s Syndrome, alcoholism and following castration. Measurement of these hormones is useful in distinguishing primary gonadal failure from secondary (Hypothalamic/Pituitary) causes of gonal failure, evaluation of menstrual disturbances and Amenorrhea. The measurements are also useful in defining menstrual cycle phases in infertility assessment of women and testicular dysfunction in males.
Tri-iodothyronine (T3), which represents only about 5% of the Thyroid Hormones, circulates in the body bound almost completely to carrier proteins, such as the major Thyroid Hormone, Thyroxine (T4). The only 0.25% free fraction is the physiologically active component, whose measurement is of value in confirming the diagnosis of Hyperthyroidism, which is marked by elevated levels of T3, T4, Free T3 and Free T4.
Free Thyroxine (T4)
A primary test for the assessment of Thyroid function, it measures the physiologically active part of Thyroxine, which is unaffected by factors that influence the levels of Thyroxine Binding Globulin (TBG). Levels of FT4 are high in Hyperthyroidism and low in Hypothyroidism.
GAD 65 Antibodies
GAD 65 Antibodies, like Insulin Antibodies, belong to a group of islet cell auto antibodies, which in many cases can be detected prior to the development of IDDM and the onset of glucose intolerance. The presence of GAD antibodies has been shown to be a strong predictive marker for the development of IDDM. The predictive value of both Insulin Antibodies and GAD 65 Antibodies can be further enhanced when they are measured together. Measurement of GAD 65 Antibodies is also useful in distinguishing between Type I and Type II Diabetes when the clinical history is not clear.
Haptoglobin is an acute phase reactant, which is elevated in inflammatory disorders such as collagen diseases and tissue destruction.
Helicobacter pylori Antibodies
Measurement of antibodies to Helicobacter pylori is used in the diagnosis and treatment ofpeptic ulcer disease. IgM antibodies represent acute disease and IgG antibodies represent chronic H.pylori infection. IgG antibodies are the most useful in monitoring treatment.
Hemoglobin A1C values are used to assess Diabetic control over time in Insulin Dependent Diabetics, particularly those whose glucose levels are labile. This testing, however, does not preclude checking blood glucose levels regularly.
Hemoglobin Electrophoresis identifies Hemoglobin variants, which help diagnose conditions such as Thalassemias and Sickle Cell Disease as causative factors for anemia.
Homocysteine may be considered an independent risk factor for cardiovascular disease. High levels have been linked to cardiovascular disease; however lowering Homocysteine levels may not improve outcomes. A high level of Homocysteine makes a person more prone to endothelial injury, which may lead to vascular inflammation and development of Atherogenesis with possible ischemic injury. HyperHomocysteinemia has been correlated with the occurrence of blood clots, heart attacks and strokes.
Inflammation is considered to play an important role in the development of cardiovascular disease. Measurement of High Sensitivity C-Reactive Protein (CRP), a marker of inflammation, also referred to as Cardiac CRP, may add to the predictive value of other markers in assessing the risk of cardiovascular and peripheral vascular disease; however elevation in levels of hs-CRP are non-specific.
Human Leukocyte Antigen B -27 (HLA B- 27)
The first association of HLA B-27 with inflammatory disease was discovered in 1972, correlating it with Ankylosing Spondylitis. This remains one of the strongest known associations of disease with HLA-B27. For example, HLA-B27 appears in 80%-90% of patients with Ankylosing Spondylitis. Expressed as a relative risk, an HLA-B27 positive individual is approximately 87 times more susceptible to developing Ankylosing Spondylitis compared to the general population. Since then, more than 100 disease associations have been made, including many ocular diseases and systemic diseases with specific ocular manifestations. These diseases also include reactive Arthritis (previously referred to as Reiter Syndrome) and Psoriatic Arthritis.
Immunoglobulin E (Total)
IgE plays a pivotal role in Type I Hypersensitivity, which manifests itself in various allergic diseases, such as Allergic Asthma, Allergic Rhinitis, Food Allergy, some types of Chronic Urticaria and Atopic Dermatitis. IgE also plays a critical role in allergic conditions, such as anaphylactic reactions to certain drugs, bee stings, and antigen preparations used in specific desensitization immunotherapy.
Immunoglobulins (IgA, IgG and IgM)
Measurement of Immunoglobulins or Antibodies, of which IgA, IgG and IgM are the three major types, is useful in assessing the body’s immune status, which may be defective leading to certain autoimmune diseases. IgE antibody levels are often high in people with allergies, whereas the role of IgD antibodies has not yet been delineated.
Type 1 or Insulin Dependent Diabetes (IDDM) is caused by the destruction of the beta cells of the Pancreas, leading to an absolute insulin deficiency. Prior to the onset of clinical symptoms which appear after 80%-90% of beta cells have been destroyed, IDDM is characterized by the presence of auto-antibodies against islet cell antigens i.e. Insulin, Glutamic Acid Decarboxylase (GAD) and Tyrosine Phosphate (IA2). Measurement of these auto antibodies is of use in the prediction, diagnosis and management of patients with IDDM. Insulin Antibodies are found predominantly, though not specifically, in young children developing IDDM. In untreated very young patients, the prevalence of Insulin Antibodies is almost 100%, but they are absent in patients with adult onset of IDDM.
Iron, TIBC, UIBC, % Saturation
These tests are useful in the differential diagnosis of anemia, especially with hypochromia and /or low MCV. The % saturation is sometimes of greater help than the total iron measurement is for assessment of iron deficiency anemia. They are also used for the evaluation of Thalassemia; possible Sideroblastic Anemia; Hemochromatosis, in which both iron and % saturation is high; for evaluation of iron toxicity, overload in renal dialysis patients and of transfusion dependent anemia.
Lyme Disease Antibodies
Lyme disease caused by the bacterium Borrelia burgdorferi and transmitted to humans through the bite of infected blacklegged ticks is the most common tick- borne disease. Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called Erythema Migrans. If left untreated, infection can spread to joints, the heart, and the nervous system. Lyme Disease is diagnosed based on symptoms, physical findings (e.g., rash); however if the initial rash is missed, positive testing for IgM antibodies, which peak in three to six weeks post-infection, indicates recent infection, whereas a positive result for only total antibodies indicates an earlier infection.
Methyl Malonic Acid
Measurement of Methyl Malonic Acid in Urine or Serum is of help in the diagnosis of Megaloblastic Anemia. Elevated levels suggest early deficiency of Vitamin B12; 90%-95% of patients with B12 deficiency have elevated levels of this compound; however increased levels are not specific to this condition.
Myoglobin is of use in the evaluation of skeletal muscle injury and in the diagnosis of Rhabdomyolysis, Dermatomyositis, Polymyositis and Muscular Dystrophy.
Nutritional Assessment Panel
The profile utilizes a unique blood test, based on technology developed at the Clayton Foundation for Research at the University of Texas which measures Lymphocyte growth to diagnose functional intracellular deficiencies of vitamins, minerals, amino acids and anti- oxidants unique to each individual patient’s metabolic processes and immune system.
Progesterone is a steroid hormone used to assess luteal phase function for the occurrence of ovulation, to determine the timing of ovulation of infertility patients and to establish the presence of a functioning Corpus Luteum. Progesterone levels are increased in Congenital Adrenal Hyperplasia (CAH) and decreased in primary or secondary Hypogonadism and in short Luteal Phase Syndrome.
Prolactin is the first line test in the work-up of Galactorrhea/Amenorrhea Syndrome. Elevated levels of Prolactin may be associated with Corpus Luteum insufficiency, anovulation and decreased bone density and/or the multiple endocrine neoplasia (MEN-1) syndrome. Prolactin levels may be checked as part of a sex hormone workup, as elevated Prolactin production can suppress the secretion of FSH and GnRH, leading to Hypogonadism, and sometimes causing Erectile Dysfunction in men. Prolactin level is also useful in assessment of Pituitary tumors in men.
Prostate Specific Antigen (PSA)
Prostate Specific Antigen (PSA) is a tumor marker widely used as an aid in the assessment of male patients for possible cancer of the Prostate. Increased levels are found both in cancer and in Prostatic Hyperplasia. The role of PSA in monitoring therapy for Prostate cancer is well established.
Reverse T3 is an isomer of T3, and is the third-most common Iodothyronine in blood accounting for approximately 0.9% of the total, and is derived almost exclusively from peripheral monodeiodinization of T4. rT3 has minimal physiological activity. The levels of rT3 increase in conditions such as Euthyroid Sick Syndrome resulting from decreased clearance, possibly from lower 5′-Deiodinase activity in the peripheral tissue or decreased liver uptake of rT3, but with unchanged production. Drugs such as Glucocorticoids and Amiodarone cause an elevation in rT3 levels.
Rheumatoid Factor which is usually comprised of IgG antibodies is present in a majority of patients with Rheumatoid Arthritis and its measurement is of help in the differential diagnosis and prognosis of arthritic disorders and of many chronic inflammatory diseases; however it is present in approximately 10% of normal individuals also.
Sex Hormone Binding Globulin (SHBG)
Sex Hormone Binding Globulin (SHBG) is the transport protein for both Testosterone and Estradiol. Decreased levels are frequently seen in Hirsutism, virilization, in obese post-menopausal women, and in women with diffuse hair loss. Elevated levels may be present in Hyperthyroidism, Testicular Feminization and male Hypogonadism. Measurement of SHBG can be an important indicator of an excessive Androgenic action where the Androgen levels may be normal, but where clinical symptoms may be indicative of Androgen excess.
Sjogren’s Syndrome Antibodies
Anti SSA and SSB antibodies are used in the diagnosis of Sjögren Syndrome, a systemic chronic inflammatory disorder characterized by lymphocytic infiltrates in exocrine organs. Most individuals with Sjögren Syndrome exhibit sicca symptoms, such as Xerophthalmia (dry eyes), Xerostomia (dry mouth), and parotid gland enlargement. In addition, numerous extra glandular features may develop including Arthralgia, Arthritis, Raynaud phenomenon, and Myalgia. Primary Sjögren syndrome occurs in the absence of another underlying Rheumatic disorder, whereas secondary Sjögren Syndrome is associated with another underlying Rheumatic disease, such as SLE, Rheumatoid Arthritis or Scleroderma.
Testosterone, Total and Free
Testosterone, the male sex hormone, of which the free fraction is the physiologically active part, is produced both by men and women and plays an important role as an anabolic hormone, throughout the body in both sexes. It affects the brain, bone and muscle mass, fat distribution, the vascular system, energy levels, genital tissues, and sexual functioning. Testosterone affects sexual features and development. In men, it is made in large amounts by the testicles. In both men and women, testosterone is made in small amounts by the adrenal glands; and, in women, by the ovaries. In adult women, excess testosterone production results in varying degrees of virilization, including hirsutism, acne, Oligo- Amenorrhea, or infertility. Mild-to-moderate testosterone elevations are usually asymptomatic in males, but can cause distressing symptoms in females.
Common causes of pronounced elevations of testosterone include genetic conditions (eg, Congenital Adrenal Hyperplasia); Adrenal, Testicular, and Ovarian tumors; and abuse of Testosterone or Gonadotropins by athletes. Decreased testosterone in females causes subtle symptoms. These may include some decline in libido and nonspecific mood changes. In males, it results in partial or complete degrees of Hypogonadism. This is characterized by changes in male secondary sexual characteristics and reproductive function. The cause is either primary or secondary/tertiary (Pituitary/Hypothalamic) testicular failure. In adult men, there also is a gradual modest, but progressive, decline in testosterone production starting between the fourth and sixth decades of life.
Thyroid Stimulating Hormone (TSH)
TSH is one of the primary tests used in the initial assessment of Thyroid function and in the differential diagnosis of both Hypo and Hyperthyroidism. It is high in Hypothyroidism and undetectable by a Third Generation assay in Hyperthyroidism. Measurement of TSH levels are also used in monitoring patients on Thyroid hormone replacement therapy and for the follow-up of patients who have had Hyperthyroidism treated with radioiodine or surgery.
Total Tri-iodothyronine (Total T3)
Total T3 is a Thyroid function test of particular use in diagnosis of T3 Thyrotoxicosis, occasionally found in Grave’s Disease in which iT3 is elevated, whereas the levels of T4 are normal. Measurement of T3 levels are of use in confirming the diagnosis of Hyperthyroidism where both T4 and T3 are elevated, as well as in the diagnosis of Hyperthyroidism when the levels of T4 are within normal limits or borderline.
Anti-Transglutaminase Antibodies (ATA) are autoantibodies against the Transglutaminase protein. IgA serum auto antibodies against tissue Transglutaminase (tTG) have an established diagnostic value in celiac disease. Celiac disease is an inflammatory disorder caused by an immune reaction to eating gluten, a protein found in wheat, barley and rye. In patients with this disease, eating gluten triggers an immune response in the small intestine. Over time, this reaction produces inflammation that damages the small intestine’s lining and prevents absorption of some nutrients.
Vitamin D (25-Hydroxy)
A number of studies have shown that Vitamin D deficiency is very common in the United States, particularly in certain high risk populations for a variety of reasons. There is strong evidence from clinical and epidemiological studies to suggest that Vitamin D deficiency may play a role in several conditions unrelated to bone, including several types of cancers, heart disease, Hypertension, Multiple Sclerosis, and Type 1 Diabetes. Measurement of the levels of this vitamin guide in the management of patients who may have deficiency of Vitamin D.