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Optimal range: 6.1 - 7.8 pH
A fecal pH test is one where a specimen of feces is tested for acidity in order to diagnose a medical condition.
- Human feces is normally acidic.
- The average pH for a healthy person is a pH of 6.6.
Fecal pH is dependent in part on fermentation of sugars. Colonic fermentation of normal amounts of carbohydrate sugars and production of fatty acids accounts for the normally slightly acidic pH.
Optimal range: 0 - 680 mcg/g
Fecal Secretory IgA is a marker of gut secretory immunity and barrier function.
Optimal range: 25.1 - 160.8 ng/mL
Fecal zonulin is a biomarker of intestinal permeability, often referred to as “leaky gut.” Zonulin is a protein that regulates the tight junctions between intestinal cells. When zonulin levels rise, these junctions loosen, allowing larger molecules — such as food proteins, toxins, or microbes — to pass into the bloodstream, which can trigger inflammation and immune responses.
Measuring zonulin in stool is considered more gut-specific than serum testing, since blood levels can also be influenced by production in other organs like the liver, heart, and brain. Elevated fecal zonulin has been associated with conditions such as celiac disease, non-celiac gluten sensitivity, Crohn’s disease, ulcerative colitis, IBS-D, metabolic syndrome, obesity, type 1 diabetes, and autoimmune disorders. Lifestyle factors like smoking, stress, and processed food intake can also affect zonulin release.
Fecal zonulin is most informative when used alongside other stool markers (such as calprotectin, secretory IgA, or anti-gliadin IgA) to help assess gut barrier integrity and distinguish between inflammatory bowel disease and other gastrointestinal disorders.
Optimal range: 30 - 400 µg/dL , 5.37 - 71.6 µmol/L , 30 - 400 ng/mL , 30 - 400 ug/L
Ferritin is a protein that serves as a storehouse for iron in the body. When iron supplies dwindle, ferritin releases some into the blood. Therefore, a blood ferritin test is an indication of how much iron is stored in the body. Iron is used primarily by red blood cells to carry oxygen to other cells, and as such Ferritin is vital to blood health.
Optimal range: 30 - 400 ug/L
Protein that stores iron. Red blood cells need iron to carry oxygen around the body such as the liver, bone marrow, and muscles. An indirect marker of the total amount of iron stored in the body; hence, serum ferritin is used as a diagnostic test for iron- deficiency anemia.
Optimal range: 15 - 150 ng/mL , 15 - 150 ug/L
Ferritin is a protein that serves as a storehouse for iron in the body.
When iron supplies dwindle, ferritin releases some into the blood. Therefore, a blood ferritin test is an indication of how much iron is stored in the body. Iron is used primarily by red blood cells to carry oxygen to other cells, and as such Ferritin is vital to blood health.
Optimal range: 44 - 215 RU/mL
FGF-23, or fibroblast growth factor 23, is a hormone-like protein that plays a critical role in phosphate and vitamin D metabolism. It is primarily produced by bone cells (osteocytes and osteoblasts) and acts mainly on the kidneys to regulate:
Phosphate excretion in urine
Vitamin D activation
Calcium-phosphate balance
FGF-23 is part of a feedback system that helps maintain normal blood phosphate levels. When phosphate levels rise, FGF-23 secretion increases to help eliminate excess phosphate through the urine and reduce vitamin D activation.
Optimal range: 0 - 1.3 Units
The FIB-4 Index, a non-invasive and widely used clinical tool, is instrumental in the assessment of liver fibrosis, particularly in patients with chronic liver diseases such as Hepatitis C and Non-Alcoholic Fatty Liver Disease (NAFLD). This index, calculated using a simple formula that incorporates age, platelet count, and liver enzyme tests (AST and ALT levels), offers a cost-effective and easily accessible means of evaluating liver health.
Optimal range: 0 - 1.29 index
If your FIB-4 Index result shows an Indeterminate risk for advanced liver fibrosis, it means that your score falls within a range where the risk of significant liver scarring (fibrosis) is uncertain. This does not confirm or rule out advanced liver fibrosis but suggests that further testing may be needed for a more definitive assessment.
The FIB-4 Index is a non-invasive biomarker used to estimate liver fibrosis risk. It is calculated using age, AST (aspartate aminotransferase), ALT (alanine aminotransferase), and platelet count. The score is typically interpreted with the following cutoffs:
If your FIB-4 result falls in the indeterminate range, your healthcare provider may:
An indeterminate FIB-4 result means further evaluation is needed to clarify your liver fibrosis status. It does not confirm serious liver disease but suggests that monitoring and possibly additional testing are advisable.
Optimal range: 0 - 11 SI
U3-RNP antibodies target the U3 small nucleolar ribonucleoprotein (U3-RNP) complex, which consists of the protein fibrillarin and U3 RNA. These antibodies are found in about 4% to 10% of patients with SSc, and are especially common in African American SSc patients (approximately 30%). U3-RNP antibodies are rarely found in patients with other autoimmune disorders; thus, the presence of these antibodies supports a SSc diagnosis.
These antibodies occur most often in dcSSc, but they can also occur in lcSSc.
U3-RNP antibodies are associated with multiorgan involvement, including the heart, kidneys, muscle, lungs, and gastrointestinal system. Their presence is an independent risk factor for the development of PAH, and PAH is the most common cause of death in U3-RNP–positive patients. Therefore, their presence indicates a poorer prognosis.
Optimal range: 0 - 370 mg/dL , 0 - 3.7 g/L
Fibrinogen is a key marker included in the Inflammation and Oxidation Test panel by Boston Heart Diagnostics, primarily due to its critical role in the body's clotting process and its association with inflammation. Essentially, fibrinogen is a blood plasma protein that's converted into fibrin by the action of the enzyme thrombin during blood clot formation. This process is crucial for stopping bleeding and initiating the healing process following an injury. However, elevated levels of fibrinogen can indicate an increased risk of clot formation within the blood vessels, which is a significant concern because it can lead to blockages, thereby increasing the risk of heart attacks and strokes.
Optimal range: 193 - 507 mg/dL , 1.93 - 5.07 g/L
It’s used to determine the level of fibrinogen in your blood. Fibrinogen, or factor I, is a blood plasma protein that’s made in the liver. Fibrinogen is one of 13 coagulation factors responsible for normal blood clotting.
Optimal range: 149 - 353 mg/dL
Fibrinogen is a soluble protein in the plasma that is broken down to fibrin by the enzyme thrombin to form clots.
Optimal range: 0 - 0.27 Score
Fibrosis Score is a non-invasive estimate of liver scarring (fibrosis) derived from routine blood tests—typically AST, ALT, platelet count—and sometimes age or body measurements. It helps determine whether liver injury from fatty liver disease (MASLD/NASH), hepatitis B or C, or alcohol use has progressed to advanced fibrosis or cirrhosis. In general, a low score indicates minimal scarring and low risk, while a high score points to significant fibrosis and the need for further evaluation, often via transient elastography (FibroScan®) or specialist assessment. Clinicians use this score to monitor liver health over time, reduce the need for biopsy, and guide treatment and lifestyle changes aimed at halting or reversing damage.
If your score falls into the low or minimal range, it suggests little to no fibrosis and likely good liver function—reassuring evidence that advanced damage is not present right now. Even so, keeping your liver healthy matters: prioritize a balanced diet, regular exercise, healthy body weight, limited alcohol, and management of metabolic risks (blood sugar, cholesterol, blood pressure). Your clinician may advise periodic re-checks of liver enzymes and fibrosis markers—typically every 1–3 years—to confirm stability and catch early changes promptly.
Reference range: F0 (no fibrosis), F0-F1 (no fibrosis), F1 (minimal fibrosis), F1-F2 (minimal fibrosis), F2 (moderate fibrosis), F3 (advanced fibrosis), 3-F4 (advanced fibrosis), F4 (severe fibrosis)
Fibrosis Stage (FibroTest® → METAVIR) expresses how much liver scarring you likely have by converting a FibroTest score (f) into METAVIR stages: f ≥ 0.00–0.21 = F0 (no fibrosis); >0.21–0.27 = F0–F1 (no fibrosis); >0.27–0.31 = F1 (minimal fibrosis); >0.31–0.48 = F1–F2 (minimal fibrosis); >0.48–0.58 = F2 (moderate fibrosis); >0.58–0.72 = F3 (advanced fibrosis); >0.72–0.74 = F3–F4 (advanced fibrosis); >0.74–1.00 = F4 (severe fibrosis/cirrhosis). Lower stages (F0–F1) suggest little to no scarring and routine lifestyle-focused care with periodic rechecks; mid stages (F1–F2) indicate rising risk and may warrant confirmatory elastography (e.g., FibroScan®) and more active treatment of the cause (metabolic, viral, alcohol-related); advanced stages (F3–F4) signal substantial scarring, higher complication risk, and the need for specialist management, imaging, and surveillance. Always interpret your number in clinical context and with the reference ranges printed on your report.
Optimal range: 0 - 1.33 Score
Noninvasive estimate of liver scarring in HCV and HBV patients, to assess need for biopsy.
Optimal range: 0.4 - 1.3 ELISA Index
ANTIBODIES ASSOCIATED WITH:
This test by itself is not diagnostic for any condition or disease
Atherosclerotic Lesions
Osteoarthritis
BODY TISSUE:
Joint
Optimal range: 0.2 - 2.2 ELISA Index
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