Evidence-Based Supplement & Herb Guides

Prostate Health Index (PHI) Test: PSA, Free PSA, p2PSA, and Prostate Cancer Risk Score

Understand what the Prostate Health Index (PHI) measures, how PSA, free PSA, and p2PSA create the score, what high PHI may mean, and how it guides biopsy decisions.

The Prostate Health Index (PHI, or phi) is a blood test that combines three prostate-specific antigen measurements—total PSA, free PSA, and proPSA (p2PSA)—into one...

Prostate-Specific Antigen (PSA) Test: Normal Range, High Levels, Prostate Cancer Risk, and Benign Causes

Learn how to interpret a PSA blood test, why there is no single normal cutoff, what benign conditions can raise PSA, how results relate to prostate cancer risk, and what follow-up may involve.

The prostate-specific antigen (PSA) test measures a protein made by prostate cells and released into the blood. It is widely used to assess prostate...

PTH-Related Peptide (PTHrP) Test: Cancer-Related High Calcium, Humoral Hypercalcemia, and Meaning

Understand why PTHrP is tested in high calcium, what elevated PTHrP can mean, how humoral hypercalcemia of malignancy is identified, and why kidney function and assay type matter.

A parathyroid hormone-related peptide (PTHrP) test is mainly used to investigate certain cases of unexplained high blood calcium, especially when cancer-related hypercalcemia is suspected....

ROMA Test: Ovarian Cancer Risk Score, CA-125, HE4, and Menopause Status

Learn what the ROMA ovarian cancer risk test measures, how CA-125, HE4, and menopause status affect the score, what high risk means, and why ROMA is not a screening test.

The Risk of Ovarian Malignancy Algorithm (ROMA) is a blood-test calculation used to estimate the likelihood that an adnexal or ovarian mass is malignant...

Serotonin Blood Test: Carcinoid Syndrome, Neuroendocrine Tumors, High Levels, and Monitoring

Learn what a serotonin blood test can show in carcinoid syndrome and neuroendocrine tumors, what high levels mean, why 5-HIAA is often preferred, and how results are monitored.

A serotonin blood test measures circulating serotonin and may be used as part of the evaluation of suspected carcinoid syndrome or a serotonin-producing neuroendocrine...

Somatostatin Blood Test: Somatostatinoma, Neuroendocrine Tumor, High Levels, and Meaning

Learn what a somatostatin blood test measures, what high levels can mean in somatostatinoma, how fasting and specimen handling affect results, and how neuroendocrine tumors are confirmed.

A somatostatin blood test measures the hormone somatostatin and is mainly used when a rare functioning neuroendocrine tumor called a somatostatinoma is suspected. Somatostatin...

Squamous Cell Carcinoma Antigen (SCC Antigen) Blood Test: High Levels, Squamous Tumors, and Monitoring

Learn what an SCC antigen blood test measures, which squamous cancers can raise it, common benign causes of high levels, and how serial SCC antigen may be used during cervical cancer follow-up.

Squamous cell carcinoma antigen (SCC antigen, SCC-Ag, or SCCA) is a blood tumor marker that can be elevated in several cancers made of squamous...

Thyroglobulin Tumor Marker Test: Thyroid Cancer Follow-Up, Recurrence, and Thyroglobulin Antibodies

Learn how thyroglobulin is used after differentiated thyroid cancer treatment, what rising Tg can mean, why Tg antibodies may hide recurrence, and how TSH and surgery type change interpretation.

Thyroglobulin (Tg) is a protein made only by normal thyroid follicular cells and most differentiated thyroid cancers. That tissue specificity makes Tg one of...

Total PSA Test: Normal Range, High Levels, Prostate Screening, and Follow-Up

Understand total PSA testing, why normal ranges are not absolute, common causes of high PSA, how screening decisions are made, and how PSA is interpreted after prostate cancer treatment.

A total prostate-specific antigen (PSA) test measures the overall concentration of PSA circulating in the blood, including PSA that is protein-bound and PSA that...

Vasoactive Intestinal Peptide (VIP) Test: VIPoma, Neuroendocrine Tumor, Watery Diarrhea, and High Levels

Learn what a VIP blood test measures, how high VIP supports VIPoma in severe watery diarrhea, why potassium loss can be dangerous, and how testing, imaging, treatment, and monitoring fit together.

A vasoactive intestinal peptide (VIP) blood test is a specialized hormone test used mainly when a VIP-secreting neuroendocrine tumor, or VIPoma, is suspected. VIPoma...

ANCA by IFA Test: c-ANCA, p-ANCA, Atypical ANCA, and Pattern Meaning

Learn how ANCA by IFA identifies c-ANCA, p-ANCA, and atypical patterns, what PR3 and MPO confirmation means, and when results need urgent follow-up.

An ANCA by IFA test looks for antibodies that bind to proteins inside neutrophils, a type of white blood cell. The laboratory reports the...

ANCA Reflex Panel: IFA Pattern, MPO Antibodies, PR3 Antibodies, and Diagnosis

Understand how an ANCA reflex panel combines IFA patterns with MPO and PR3 antibodies, how result combinations relate to vasculitis, and what follow-up tests matter.

An ANCA reflex panel is a staged blood-testing process used when clinicians suspect antineutrophil cytoplasmic antibody–associated vasculitis. Depending on the laboratory, testing may begin...

ANCA Test: Positive, Negative, Pattern, Vasculitis Risk, and Meaning

Learn what positive, negative, c-ANCA, p-ANCA, PR3, and MPO results mean, how they change vasculitis risk, and which symptoms require urgent follow-up.

An ANCA test helps evaluate whether symptoms could come from a group of small-vessel inflammatory diseases called ANCA-associated vasculitis. A positive result can raise...

Angiotensin-Converting Enzyme (ACE) Test: Sarcoidosis, Granulomatous Disease, and Meaning

Learn what a high, normal, or low ACE test means, why ACE cannot diagnose sarcoidosis alone, and how medications, imaging, biopsy, and organ testing guide follow-up.

The angiotensin-converting enzyme (ACE) blood test measures the activity of ACE in serum. Clinicians sometimes use it as a supporting marker when sarcoidosis is...

Anti-Glomerular Basement Membrane (Anti-GBM) Test: Goodpasture Syndrome and Kidney-Lung Disease

Understand what positive, negative, and borderline anti-GBM test results mean, how Goodpasture syndrome affects the kidneys and lungs, and why biopsy, ANCA testing, and urgent treatment matter.

The anti-glomerular basement membrane test looks for antibodies that can rapidly injure the kidney’s filtering capillaries and, in some people, the air sacs of...

Behcet Disease Blood Test Panel: HLA-B51, CRP, ESR, and Inflammation Markers

Learn how HLA-B51, CRP, ESR, blood counts, and organ-specific tests are used in Behçet disease, why no blood panel confirms the diagnosis, and which symptoms need urgent care.

A Behçet disease blood test panel can support an evaluation, but it cannot confirm or rule out Behçet disease by itself. The diagnosis rests...

c-ANCA Test: Granulomatosis With Polyangiitis, PR3 Antibodies, and Meaning

Learn what a positive or negative c-ANCA test means, how PR3 antibodies support granulomatosis with polyangiitis, why results can mismatch, and when biopsy or urgent care is needed.

A c-ANCA result describes a cytoplasmic staining pattern seen when a patient’s antibodies bind to neutrophils in an indirect immunofluorescence test. In granulomatosis with...

CH50 Test for Vasculitis: Complement Activity, Low Levels, and Immune Meaning

Learn what a low, normal, or high CH50 test means in vasculitis, how CH50 differs from C3, C4, and AH50, and why immune consumption, deficiency, treatment, and sample handling matter.

The CH50 test measures whether the classical complement pathway can complete a full immune reaction from its early proteins through the membrane attack complex....

Complement C3 and C4 Test for Vasculitis: Low Levels, Immune Complex Disease, and Meaning

Understand complement C3 and C4 results in vasculitis, including low C4, low C3 and C4, immune-complex disease, normal levels, and next tests.

Complement C3 and C4 tests measure two abundant proteins in the complement system, an immune network that helps antibodies clear microbes and damaged cells....

Cryofibrinogen Test: Blood Vessel Inflammation, Clotting, and Cold-Related Symptoms

Learn what a cryofibrinogen test detects, why warm plasma handling matters, and how positive results relate to cold-triggered clotting and vasculitis.

A cryofibrinogen test looks for a cold-precipitable protein complex in plasma. The complex usually contains fibrinogen, fibrin, fibronectin, and smaller amounts of other proteins....