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Diagnostic Tests

Physicians use a variety of procedures and tests to diagnose diabetes, digestive, kidney, and other diseases and conditions. Information about many of these tests is available below.

  • A1C Test and Diabetes

    Defines and explains the A1C diabetes blood test. Discusses using the test for diagnosis of diabetes and prediabetes and monitoring of glucose levels in people with Type 1 or Type 2 diabetes.

  • A1C Test and Race/Ethnicity

    Describes hemoglobin variants and how they can cause false results for the A1C test. Discusses how false results can affect diabetes diagnosis and care in people with hemoglobin variants.

  • Diabetes and Prediabetes Tests

    Provides a concise summary for health care providers of blood tests for diabetes and prediabetes, covering uses, technical features, and pros and cons of different tests

  • Sickle Cell Trait and Other Hemoglobinopathies and Diabetes (For Providers)

    Explains how the A1C test can lead to misdiagnosis, overtreatment, or undertreatment of diabetes in people with hemoglobinopathies. Explains when to suspect a patient has a variant.

  • Colonoscopy

    A procedure that uses a long, flexible, narrow tube with a light and tiny camera on one end to look inside your rectum and entire colon. Colonoscopy can show irritated and swollen tissue, ulcers, and polyps.

  • Endoscopic Retrograde Cholangiopancreatography

    Describes the purpose of the test, how patients can prepare for it, and what patients can expect during and after the procedure.

  • Flexible Sigmoidoscopy

    Describes the purpose of the test, how patients can prepare for it, and what patients can expect during and after the procedure. This publication is also available in Spanish.

  • Lower GI Series

    Provides general information about the lower gastrointestinal (GI) x-ray series. Describes the purpose of the test and what patients can expect before, during, and after the procedure. This publication is also available in Spanish.

  • Celiac Disease Tests

    Describes tests that identify serological and genetic markers associated with celiac disease. If tests indicate the possibility of celiac disease, a biopsy determines diagnosis.

  • Upper GI Endoscopy

    A procedure in which a doctor uses an instrument called an endoscope to see the lining of your upper GI tract. Doctors use upper GI endoscopy to find, and sometimes treat, problems in the upper GI tract.

  • Upper GI Series

    Upper gastronintestinal (GI) endoscopy is a procedure in which a doctor uses an instrument called an endoscope to see the lining of your upper GI tract. Doctors use upper GI endoscopy to find, and sometimes treat, problems in the upper GI tract.

  • Virtual Colonoscopy

    Provides information about virtual colonoscopy. Describes the purpose of the test, how patients can prepare for it, and what patients can expect during and after the procedure.

  • Thyroid Tests

    Describes the different tests used to evaluate thyroid function and diagnose thyroid disease. Includes typical thyroid test results seen in thyroid diseases.

  • Kidney Biopsy

    Describes the procedure and possible reasons for performing this diagnostic test. Outlines the preparations for and explains what patients can expect during and after the test.

  • Liver Biopsy

    Provides general information about liver biopsy. Describes the purpose of the test, how patients can prepare for it, and what patients can expect during and after the procedure.

  • Cystoscopy and Ureteroscopy

    Outlines possible reasons for cystoscopy and ureteroscopy and explains the preparations involved. Describes the procedures in detail, as well as what patients can expect afterward.

  • Urinary Tract Imaging

    Explains the range of imaging technologies used to evaluate the urinary tract, including ultrasound, conventional radiology, magnetic resonance imaging, and computerized tomography.

  • Prostate Tests

    Provides general information about prostate and problems. Describes several tests, including digital rectal exam, PSA blood test, urinalysis, and others.

  • Urodynamic Testing

    Describes normal bladder function, as well as problems in the urinary system that may require urodynamic testing. Discusses different urodynamic procedures and why they are used.