The diagnosis of medullary cystic kidney disease can be done via a physical exam. Further tests/exams are as follows:

- A routine blood test called the serum creatinine can be done. Creatinine is a breakdown product from the muscle, as kidney function declines, the amount of blood creatinine goes up. Thus, most affected individuals have no symptoms of MCKD, but find that they have the condition due to an elevation in the blood creatinine level.

- Affected individuals also have an elevation in the blood uric acid level. In MCKD, the kidney has difficulty getting rid of uric acid. One can find out that the uric acid level in the blood is high when a blood test is done. Gout is caused by high uric acid levels, and thus patients often have gout.

- A kidney ultrasound in this condition usually shows normal or small sized kidneys (occasionally cysts are present). However, since cysts are present in many normal individuals, these cysts are not helpful in making a diagnosis, therefore a kidney biopsy can be done to determine if the individual has this disease. Kidney biopsy is a procedure where a needle is inserted into the kidney and removes a small piece of kidney tissue. This tissue is then examined under a microscope.

- Definitive testing and diagnosis of MCKD can be made by analyzing the UMOD gene for mutations, this can be done by a blood test.

It is possible to analyze urine samples in determining albumin, hemoglobin and myoglobin with an optimized MEKC method.

Classically, MSK is seen as hyperdense papillae with clusters of small stones on ultrasound examination of the kidney or with an abdominal x-ray. The irregular (ectatic) collecting ducts are often seen in MSK, which are sometimes described as having a "paintbrush-like" appearance, are best seen on intravenous urography. However, IV urography has been largely replaced by contrast-enhanced, high-resolution helical CT with digital reconstruction.

A doctor normally can diagnose renal glycosuria when a routine urine test (Urinalysis) detects glucose in the urine, while a blood test indicates that the blood glucose level is normal.

Conventionally, proteinuria is diagnosed by a simple dipstick test, although it is possible for the test to give a false negative reading, even with nephrotic range proteinuria if the urine is dilute. False negatives may also occur if the protein in the urine is composed mainly of globulins or Bence Jones proteins because the reagent on the test strips, bromophenol blue, is highly specific for albumin. Traditionally, dipstick protein tests would be quantified by measuring the total quantity of protein in a 24-hour urine collection test, and abnormal globulins by specific requests for protein electrophoresis. Trace results may be produced in response to excretion of Tamm–Horsfall mucoprotein.

More recently developed technology detects human serum albumin (HSA) through the use of liquid crystals (LCs). The presence of HSA molecules disrupts the LCs supported on the AHSA-decorated slides thereby producing bright optical signals which are easily distinguishable. Using this assay, concentrations of HSA as low as 15 µg/mL can be detected.

Alternatively, the concentration of protein in the urine may be compared to the creatinine level in a spot urine sample. This is termed the protein/creatinine ratio. The 2005 UK Chronic Kidney Disease guidelines states protein/creatinine ratio is a better test than 24-hour urinary protein measurement. Proteinuria is defined as a protein/creatinine ratio greater than 45 mg/mmol (which is equivalent to albumin/creatinine ratio of greater than 30 mg/mmol or approximately 300 mg/g) with very high levels of proteinuria having a ratio greater than 100 mg/mmol.

Protein dipstick measurements should not be confused with the amount of protein detected on a test for microalbuminuria which denotes values for protein for urine in mg/day versus urine protein dipstick values which denote values for protein in mg/dL. That is, there is a basal level of proteinuria that can occur below 30 mg/day which is considered non-pathology. Values between 30–300 mg/day are termed microalbuminuria which is considered pathologic. Urine protein lab values for microalbumin of >30 mg/day correspond to a detection level within the "trace" to "1+" range of a urine dipstick protein assay. Therefore, positive indication of any protein detected on a urine dipstick assay obviates any need to perform a urine microalbumin test as the upper limit for microalbuminuria has already been exceeded.

In terms of treatment/management for medullary cystic kidney disease, at present there are no specific therapies for this disease, and there are no specific diets known to slow progression of the disease. However, management for the symptoms can be dealt with as follows: erythropoietin is used to treat anemia, and growth hormone is used when growth becomes an issue. Additionally, a renal transplant may be needed at some point.

Finally, foods that contain potassium and phosphate must be reduced

As of today, no agreed-upon treatment of Dent's disease is known and no therapy has been formally accepted. Most treatment measures are supportive in nature:

- Thiazide diuretics (i.e. hydrochlorothiazide) have been used with success in reducing the calcium output in urine, but they are also known to cause hypokalemia.

- In rats with diabetes insipidus, thiazide diuretics inhibit the NaCl cotransporter in the renal distal convoluted tubule, leading indirectly to less water and solutes being delivered to the distal tubule. The impairment of Na transport in the distal convoluted tubule induces natriuresis and water loss, while increasing the reabsorption of calcium in this segment in a manner unrelated to sodium transport.

- Amiloride also increases distal tubular calcium reabsorption and has been used as a therapy for idiopathic hypercalciuria.

- A combination of 25 mg of chlorthalidone plus 5 mg of amiloride daily led to a substantial reduction in urine calcium in Dent's patients, but urine pH was "significantly higher in patients with Dent’s disease than in those with idiopathic hypercalciuria (P < 0.03), and supersaturation for uric acid was consequently lower (P < 0.03)."

- For patients with osteomalacia, vitamin D or derivatives have been employed, apparently with success.

- Some lab tests on mice with CLC-5-related tubular damage showed a high-citrate diet preserved kidney function and delayed progress of kidney disease.

Although normally benign, idiopathic renal hypouricemia may increase the risk of exercise-induced acute renal failure.

Individuals with renal papillary necrosis due to excess use of analgesic have an elevated risk of epithelial tumors, hence a urine cytology exam is useful. In terms of imaging this condition can be identified by retrograde pyelography (RGP). The diagnosis of renal papillary necrosis is therefore done via:

Treatment consists of oral bicarbonate supplementation. However, this will increase urinary bicarbonate wasting and may well promote a bicarbonate . The amount of bicarbonate given may have to be very large to stay ahead of the urinary losses. Correction with oral bicarbonate may exacerbate urinary potassium losses and precipitate hypokalemia. As with dRTA, reversal of the chronic acidosis should reverse bone demineralization.

Thiazide diuretics can also be used as treatment by making use of contraction alkalosis caused by them.

Uric acid clearance should also be performed, increase in clearance points to proximal tubular defects in the kidney, normal or reduced clearance points to a defect in xanthine oxidase.

In people with microscopic hematuria, it is important to rule out any possible confounders such as menstruation in women, possible presence of semen in sample or recent rigorous exercise. In menstruating women, tests should be repeated during non-bleeding parts of their cycles. In individuals with history of recent rigorous exercise, urinalysis should be repeated 4–6 weeks following cessation of exercise. All women of child-bearing age should undergo a pregnancy test, and if positive should receive an ultrasound of their kidneys and bladder with further invasive diagnostic work-up deferred until completion of pregnancy.

If diagnostic work-up has been unyielding so far or the aforementioned risk factors are present, it is important to begin a thorough work-up for possible malignancy especially of the bladder and kidney by referring to a Urologist to look at the urethra and bladder with a cystoscopy and also performing additional imaging using CT urography, which provides a thorough view of the complete urinary system.

For individuals with persistent hematuria with no immediate identifiable cause, urinalysis should be repeated once a year, and if it is negative for 2 years then you can stop repeating the tests. However, if it is positive for 3 years, repeat anatomic evaluation should be done.

For people with visible hematuria and evidence of blood clots, further imaging with an abdominal CT scan should be done and an urgent referral to a urologist made. Otherwise, the next step involves determining if source of bleeding is glomerular in nature as evidenced by presence of inappropriately shaped/dysmorphic red blood cells, presence of protein in the urine, new or worsening hypertension or swelling. If source is glomerular patients should be referred to a nephrologist for further evaluation. Non-glomerular source of bleeding will usually require further work-up by a urologist.

It is associated with SLC5A2, coding the sodium-glucose cotransporter 2.

Treatment of renal papillary necrosis is supportive, any obstruction (urethral) can be dealt with via stenting. This condition is not linked to a higher possibility of renal failure. Control of infection is important, thus antimicrobial treatment is begun, so as to avert surgery (should the infection not respond).

Often, aggressive treatment is unnecessary for people with MSK disease that does not cause any symptoms (asymptomatic). In such cases, treatment may consist of maintaining adequate fluid intake, with the goal of decreasing the risk of developing kidney stones (nephrolithiasis). Cases of recurrent kidney stone formation may warrant evaluation for possible underlying metabolic abnormalities.

In patients with low levels of citrate in the urine (hypocitraturia) and incomplete distal renal tubular acidosis, treatment with potassium citrate helps prevent the formation of new kidney stones. Urinary tract infections, when they occur, should also be treated.

Patients with the more rare form of MSK marked by chronic pain typically require pain management. Non-obstructing stones in MSK can be associated with significant and chronic pain even if they're not passing. The pain in this situation can be constant. It is not certain what causes this pain but researchers have proposed that the small numerous stones seen in MSK may cause obstruction of the small tubules and collecting ducts in the kidney which could lead to the pain. This pain can often be debilitating and treatment is challenging. Narcotic medication even with large quantities is sometimes not adequate. Some success with pain control has been reported using laser lithotripsy (called “ureteroscopic laser papillotomy”).

Based on studies conducted in the United States, the prognosis for individuals with ALECT2 amyloidosis is guarded, particularly because they are elderly and their kidney disease is usually well-advanced at the time of presentation. End-stage renal disease develops in 1 out of 3 patients and has a median renal survival of 62 months. A suggested prognostic tool is to track creatinine levels in ALect2 patients. The attached Figure gives survival plotss for individuals with LECT2 renal amyloidosis and serum creatinine levels less than 2 mg/100 ml versus 2 mg/100 ml or greater than 2 mg/100 ml. The results show that afflicted individuals with lower creatinine levels have a ~four-fold higher survival rate.

For an adult patient with isolated hematuria, tests such as ultrasound of the kidney and cystoscopy are usually done first to pinpoint the source of the bleeding. These tests would rule out kidney stones and bladder cancer, two other common urological causes of hematuria. In children and younger adults, the history and association with respiratory infection can raise the suspicion of IgA nephropathy. A kidney biopsy is necessary to confirm the diagnosis. The biopsy specimen shows proliferation of the mesangium, with IgA deposits on immunofluorescence and electron microscopy. However, patients with isolated microscopic hematuria (i.e. without associated proteinuria and with normal kidney function) are not usually biopsied since this is associated with an excellent prognosis. A urinalysis will show red blood cells, usually as red cell urinary casts. Proteinuria, usually less than 2 grams per day, also may be present. Other renal causes of isolated hematuria include thin basement membrane disease and Alport syndrome, the latter being a hereditary disease associated with hearing impairment and eye problems.

Other blood tests done to aid in the diagnosis include CRP or ESR, complement levels, ANA, and LDH. Protein electrophoresis and immunoglobulin levels can show increased IgA in 50% of all patients.

Dent disease 2 (nephrolithiasis type 2) is associated with the "OCRL" gene. Both Lowe syndrome (oculocerebrorenal syndrome) and Dent disease can be caused by truncating or missense mutations in "OCRL".

Familial disorders

- Cystinosis

- Galactosemia

- Glycogen storage disease (type I)

- Hereditary fructose intolerance

- Lowe syndrome

- Tyrosinemia

- Wilson's disease

Acquired disorders

- Amyloidosis

- Multiple myeloma

- Paroxysmal nocturnal hemoglobinuria

- Toxins, such as HAART, ifosfamide, lead, and cadmium

LECT2 amyloidosis is diagnosed by a kidney biopsy which reveals two key findings: a) histological evidence of Congo red staining material deposited in the interstitial, mesangial, glomerular, and/or vascular areas of the kidney and b) the identification of these deposits as containing mainly ALECT2 as identified by proteomics methodologies. Kidney biopsy shows the presence of LECT2-based amyloid predominantly in the renal cortex interstitium, glomeruli, and arterioles. LECT2 amyloidosis can be distinguished from AL amyloidosis, the most common form of amyloidosis (~85% of total cases), by testing their blood for the presence of high levels of a clonal immunoglobulin light chain. If the patient tests negative for this light chain, positive Congo Red staining of the kidney biopsy strongly suggests LECT2 amyloidosis.

Male gender, proteinuria (especially > 2 g/day), hypertension, smoking, hyperlipidemia, older age, familial disease and elevated creatinine concentrations are markers of a poor outcome. Frank hematuria has shown discordant results with most studies showing a better prognosis, perhaps related to the early diagnosis, except for one group which reported a poorer prognosis. Proteinuria and hypertension are the most powerful prognostic factors in this group.

There are certain other features on kidney biopsy such as interstitial scarring which are associated with a poor prognosis. ACE gene polymorphism has been recently shown to have an impact with the DD genotype associated more commonly with progression to kidney failure.

The diagnosis of renal artery stenosis can use many techniques to determine if the condition is present, a clinical prediction rule is available to guide diagnosis.

Among the diagnostic techniques are:

- Doppler ultrasound study of the kidneys

- refractory hypertension

- auscultation (with stethoscope) - bruit ("rushing" sound)

- captopril challenge test

- captopril test dose effect on the differential renal function as measured by MAG3 scan.

- renal artery arteriogram.

In children and some adults, FSGS presents as a nephrotic syndrome, which is characterized by edema (associated with weight gain), hypoalbuminemia (low serum albumin, a protein in the blood), hyperlipidemia and hypertension (high blood pressure). In adults, it may also present as kidney failure and proteinuria, without a full-blown nephrotic syndrome.

Focal segmental glomerulosclerosis (FSGS) is a cause of nephrotic syndrome in children and adolescents, as well as a leading cause of kidney failure in adults. It is also known as "focal glomerular sclerosis" or "focal nodular glomerulosclerosis". It accounts for about a sixth of the cases of nephrotic syndrome. (Minimal change disease (MCD) is by far the most common cause of nephrotic syndrome in children: MCD and primary FSGS may have a similar cause.)