Editing Nephrology (section)

==Diagnosis==
[[History]] and [[physical examination]] are central to the diagnostic workup in nephrology. The history typically includes the present illness, family history, general medical history, diet, medication use, drug use and occupation. The physical examination typically includes an assessment of volume state, blood pressure, heart, lungs, peripheral arteries, joints, abdomen and [[Latus (anatomy)|flank]]. A rash may be relevant too, especially as an indicator of autoimmune disease.

Examination of the urine ([[urinalysis]]) allows a direct assessment for possible kidney problems, which may be suggested by appearance of blood in the urine ([[hematuria]]), protein in the urine ([[proteinuria]]), pus cells in the urine ([[pyuria]]) or cancer cells in the urine. A 24-hour urine collection used to be used to quantify daily protein loss (see [[proteinuria]]), urine output, [[creatinine clearance]] or electrolyte handling by the [[renal tubules]]. It is now more common to measure protein loss from a small random sample of urine.

Basic blood tests can be used to check the concentration of [[hemoglobin]], white count, [[platelets]], sodium, potassium, chloride, bicarbonate, [[urea]], [[creatinine]], albumin, calcium, magnesium, phosphate, alkaline phosphatase and [[parathyroid hormone]] (PTH) in the blood. All of these may be affected by kidney problems. The serum creatinine concentration is the most important blood test as it is used to estimate the function of the kidney, called the [[creatinine clearance]] or estimated [[glomerular filtration rate]] (GFR).

It is a good idea for patients with longterm kidney disease to know an up-to-date list of medications, and their latest blood tests, especially the blood creatinine level. In the United Kingdom, blood tests can monitored online by the patient, through a website called RenalPatientView.

More specialized tests can be ordered to discover or link certain systemic diseases to kidney failure such as infections ([[hepatitis B]], [[hepatitis C]]), [[autoimmune conditions]] ([[Lupus nephritis|systemic lupus erythematosus]], [[ANCA-associated vasculitides|ANCA vasculitis]]), [[paraproteinemias]] ([[amyloidosis]], [[multiple myeloma]]) and [[Metabolic disorder|metabolic diseases]] ([[diabetes]], [[cystinosis]]).

Structural abnormalities of the kidneys are identified with imaging tests. These may include [[Medical ultrasonography|Medical ultrasonography/ultrasound]], [[Computed axial tomography|computed axial tomography (CT)]], [[scintigraphy]] ([[nuclear medicine]]), [[angiography]] or [[magnetic resonance imaging|magnetic resonance imaging (MRI)]].

In certain circumstances, less invasive testing may not provide a certain diagnosis. Where definitive diagnosis is required, a [[biopsy]] of the kidney ([[renal biopsy]]) may be performed. This typically involves the insertion, under [[local anaesthetic]] and ultrasound or CT guidance, of a [[core biopsy]] needle into the kidney to obtain a small sample of kidney tissue. The kidney tissue is then examined under a microscope, allowing direct visualization of the changes occurring within the kidney. Additionally, the pathology may also [[staging (pathology)|stage]] a problem affecting the kidney, allowing some degree of [[Prognosis|prognostication]]. In some circumstances, kidney biopsy will also be used to monitor response to treatment and identify early [[relapse]]. A transplant kidney biopsy may also be performed to look for rejection of the kidney.