Guidelines for referral to a nephrologist vary between countries. Though most would agree that nephrology referral is required by Stage 4 CKD (when eGFR/1.73m is less than 30 ml/min; or decreasing by more than 3 ml/min/year); and may be useful at an earlier stage (e.g. CKD3) when urine albumin-to-creatinine ratio is more than 30 mg/mmol, when blood pressure is difficult to control, or when hematuria or other findings suggest either a primarily glomerular disorder or secondary disease amenable to specific treatment. Other benefits of early nephrology referral include proper patient education regarding options for renal replacement therapy as well as pre-emptive transplantation, and timely workup and placement of an arteriovenous fistula in those patients opting for future hemodialysis

Screening those who have neither symptoms nor risk factors for CKD is not recommended. Those who should be screened include: those with hypertension or history of cardiovascular disease, those with diabetes or marked obesity, those aged > 60 years, subjects with indigenous racial origin, those with a history of kidney disease in the past and subjects who have relatives who had kidney disease requiring dialysis. Screening should include calculation of estimated GFR from the serum creatinine level, and measurement of urine albumin-to-creatinine ratio (ACR) in a first-morning urine specimen (this reflects the amount of a protein called albumin in the urine), as well as a urine dipstick screen for hematuria. The GFR (glomerular filtration rate) is derived from the serum creatinine and is proportional to 1/creatinine, i.e. it is a reciprocal relationship (the higher the creatinine, the lower the GFR). It reflects one aspect of kidney function: how efficiently the glomeruli (filtering units) work. But as they make up <5% of the mass of the kidney, the GFR does not indicate all aspects of kidney health and function. This can be done by combining the GFR level with the clinical assessment of the patient (especially fluid state) and measuring the levels of hemoglobin, potassium, phosphate and parathyroid hormone (PTH). Normal GFR is 90-120 mLs/min. The units of creatinine vary from country to country.

Usually, the diagnosis of ADPKD is initially performed by renal imaging using ultrasound, CT scan, or MRI. However, molecular diagnostics can be necessary in the following situations: 1- when a definite diagnosis is required in young individuals, such as a potential living related donor in an affected family with equivocal imaging data; 2- in patients with a negative family history of ADPKD, because of potential phenotypic overlap with several other kidney cystic diseases; 3- in families affected by early-onset polycystic kidney disease, since in this cases hypomorphic alleles and/or oligogenic inheritance can be involved; and 4- in patients requesting genetic counseling, especially in couples wishing a pre-implantation genetic diagnosis.

The findings of large echogenic kidneys without distinct macroscopic cysts in an infant/child at 50% risk for ADPKD are diagnostic. In the absence of a family history of ADPKD, the presence of bilateral renal enlargement and cysts, with or without the presence of hepatic cysts, and the absence of other manifestations suggestive of a different renal cystic disease provide presumptive, but not definite, evidence for the diagnosis. In some cases, intracranial aneurysms can be an associated sign of ADPKD, and screening can be recommended for patients with a family history of intracranial aneurysm.

Molecular genetic testing by linkage analysis or direct mutation screening is clinically available; however, genetic heterogeneity is a significant complication to molecular genetic testing. Sometimes a relatively large number of affected family members need to be tested in order to establish which one of the two possible genes is responsible within each family. The large size and complexity of PKD1 and PKD2 genes, as well as marked allelic heterogeneity, present obstacles to molecular testing by direct DNA analysis. The sensitivity of testing is nearly 100% for all patients with ADPKD who are age 30 years or older and for younger patients with PKD1 mutations; these criteria are only 67% sensitive for patients with PKD2 mutations who are younger than age 30 years.

Polycystic kidney disease can be ascertained via a CT scan of abdomen, as well as, an MRI and ultrasound of the same area. A physical exam/test can reveal enlarged liver, heart murmurs and elevated blood pressure

ADPKD individuals might have a normal life; conversely, ARPKD can cause kidney dysfunction and can lead to kidney failure by the age of 40-60. ADPKD1 and ADPKD2 are very different, in that ADPKD2 is much milder.

Currently, there are no therapies proven effective to prevent the progression of polycystic kidney disease (autosomal dominant).

Chronic kidney failure is measured in five stages, which are calculated using a patient’s GFR, or glomerular filtration rate. Stage 1 CKD is mildly diminished renal function, with few overt symptoms. Stages 2 and 3 need increasing levels of supportive care from their medical providers to slow and treat their renal dysfunction. Patients in stages 4 and 5 usually require preparation of the patient towards active treatment in order to survive. Stage 5 CKD is considered a severe illness and requires some form of renal replacement therapy (dialysis) or kidney transplant whenever feasible.

- Glomerular filtration rate

A normal GFR varies according to many factors, including sex, age, body size and ethnic background. Renal professionals consider the glomerular filtration rate (GFR) to be the best overall index of kidney function. The National Kidney Foundation offers an easy to use on-line GFR calculator for anyone who is interested in knowing their glomerular filtration rate. (A serum creatinine level, a simple blood test, is needed to use the calculator.)

The standard diagnostic workup of suspected kidney disease is history & examination, as well as a urine test strip. Also, renal ultrasonography is essential in the diagnosis and management of kidney-related diseases.

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.

Ultrasonography is the primary method to evaluate autosomal recessive polycystic kidney disease, particularly in the perinatal and neonatal.

Before the advancement of modern medicine, renal failure was often referred to as uremic poisoning. Uremia was the term for the contamination of the blood with urine. It is the presence of an excessive amount of urea in blood. Starting around 1847, this included reduced urine output, which was thought to be caused by the urine mixing with the blood instead of being voided through the urethra. The term "uremia" is now used for the illness accompanying kidney failure.

The diagnosis of nephronophthisis can be obtained via a renal ultrasound, family history and clinical history of the affected individual according to Stockman, et al.

In ADPKD patients, gradual cyst development and expansion result in kidney enlargement, and during the course of the disease, glomerular filtration rate (GFR) remains normal for decades before kidney function starts to progressively deteriorate, making early prediction of renal outcome difficult. The CRISP study, mentioned in the treatment section above, contributed to build a strong rationale supporting the prognostic value of total kidney volume (TKV) in ADPKD; TKV (evaluated by MRI) increases steadily and a higher rate of kidney enlargement correlated with accelerated decline of GFR, while patient height-adjusted TKV (HtTKV) ≥600 ml/m predicts the development of stage 3 chronic kidney disease within 8 years.

Besides TKV and HtTKV, the estimated glomerular filtration rate (eGFR) has also been tentatively used to predict the progression of ADPKD. After the analysis of CT or MRI scans of 590 patients with ADPKD treated at the Mayo Translational Polycystic Kidney Disease Center, Irazabal and colleagues developed an imaging-based classification system to predict the rate of eGFR decline in patients with ADPKD. In this prognostic method, patients are divided into five subclasses of estimated kidney growth rates according to age-specific HtTKV ranges (1A, 6.0%) as delineated in the CRISP study. The decline in eGFR over the years following initial TKV measurement is significantly different between all five patient subclasses, with those in subclass 1E having the most rapid decline.

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

Millions of people across the world suffer from kidney disease. Of those millions, several thousand will eventually or do need kidney transplants. Out of those millions in the world, 16,500 in the United States needed a kidney transplant in 2008. Of those 16,500 people, 5,000 died while waiting for a transplant. Currently, there is a shortage of donors, and in 2007 there were only 64,606 kidney transplants in the world. This shortage of donors is causing countries to place monetary value on kidneys. Countries such as Iran and Singapore are eliminating their lists by paying their citizens to donate. Also, the black market accounts for 5-10 percent of transplants that occur worldwide. The act of buying an organ through the black market is illegal in the United States. To be put on the waiting list for a kidney transplant, patients must first be referred by a physician, then they must choose and contact a donor hospital. Once they choose a donor hospital, patients must then receive an evaluation to make sure they are sustainable to receive a transplant. In order to be a match for a kidney transplant, patients must match blood type and human leukocyte antigen factors with their donors. They must also have no reactions to the antibodies from the donor’s kidneys.

The treatment options for autosomal recessive polycystic kidney disease, given there is no current cure, are:

- Medications for hypertension

- Medications and/or surgery for pain

- Antibiotics for infection

- Kidney transplantation(in serious cases)

- Dialysis (if renal failure)

The management of this condition can be done via-improvement of any electrolyte imbalance, as well as, hypertension and anemia treatment as the individuals condition warrants.

Many forms of cystic kidney disease can be detected in children prior to birth. Abnormalities which only affect one kidney are unlikely to cause a problem with the healthy arrival of a baby. Abnormalities which affect both kidneys can have an effect on the baby's amniotic fluid volume which can in turn lead to problems with lung development. Some forms of obstruction can be very hard to differentiate from cystic renal disease on early scans.

It is an autosomal recessive disease.

Sonography shows bilateral small kidneys with loss of corticomedullary junction and multiple cysts only in the medulla. Cysts may only be seen if they are large enough, they are rarely visible early in disease.

Patients with medullary cystic disease present with similar features as juvenile nephronophthisis but they can be differentiated by:

1. Absence of growth retardation.

2. Age of presentation is third or fourth decade.

3. Hypertension may occur (in JN, hypertension is not seen).

In polycystic kidney disease, there is bilateral enlargement of kidneys (small kidneys in JN).

The complex cyst can be further evaluated with doppler ultrasonography, and for Bosniak classification and follow-up of complex cysts, either contrast-enhanced ultrasound (CEUS) or contrast CT is used.

Cystic kidney disease refers to a wide range of hereditary, developmental, and acquired conditions. With the inclusion of neoplasms with cystic changes, over 40 classifications and subtypes have been identified. Depending on the disease classification, the presentation of disease may be from birth, or much later into adult life. Cystic disease may involve one or both kidneys and may or may not occur in the presence of other anomalies. A higher incidence of cystic kidney disease is found in the male population and prevalence increases with age. Renal cysts have been reported in more than 50% of patients over the age of 50. Typically, cysts grow up to 2.88 mm annually and cause related pain and/or hemorrhage.

Of the cystic kidney diseases, the most common is Polycystic kidney disease; having two prevalent sub-types: autosomal recessive and autosomal dominant polycystic kidney disease. Autosomal Recessive Polycystic Kidney Disease (ARPKD) is primarily diagnosed in infants and young children. Autosomal dominant polycystic kidney disease (ADPKD) is most often diagnosed in adulthood.

Another example of cystic kidney disease is Medullary sponge kidney.

It is the most common genetic cause of end stage renal disease (renal failure) in childhood and adolescence.

This system is more directly focused on the most appropriate management. These alternatives are broadly to ignore the cyst, schedule follow-up or perform a surgical excision of it. When a cyst shows discrepancy in severity across categories, it is the most worrisome feature that is used in deciding about management. There is no established rule regarding the follow-up frequency, but one possibility is after 6 months, which can later be doubled if unchanged.

Differential diagnosis includes nephrogenic diabetes insipidus, neurogenic/central diabetes insipidus and psychogenic polydipsia. They may be differentiated by using the water deprivation test.

Recently, lab assays for ADH are available and can aid in diagnosis.

If able to rehydrate properly, sodium concentration should be nearer to the maximum of the normal range. This, however, is not a diagnostic finding, as it depends on patient hydration.

DDAVP can also be used; if the patient is able to concentrate urine following administration of DDAVP, then the cause of the diabetes insipidus is neurogenic; if no response occurs to DDAVP administration, then the cause is likely to be nephrogenic.

The first steps taken to diagnose this condition are consideration of the signs and symptoms, and a medical history (the detailed medical review of past health state) to evaluate any risk factors. Based on the symptoms presented, a range of biochemical tests (using blood and/or urine samples) may also be considered as part of the screening process to provide sufficient quantitative analysis of any differences in electrolytes, renal and liver function, and blood clotting times. Upon physical examination, palpation of the abdomen may reveal the presence of a mass or an organ enlargement.

Although this disease lacks characterization in the early stages of tumor development, considerations based on diverse clinical manifestations, as well as resistance to radiation and chemotherapy are important. The main diagnostic tools for detecting renal cell carcinoma are ultrasound, computed tomography (CT) scanning and magnetic resonance imaging (MRI) of the kidneys.

Blood chemistry tests are conducted if renal cell carcinoma is suspected as cancer has the potential to elevate levels of particular chemicals in blood. For example, liver enzymes such as aspartate aminotransferase [AST] and alanine aminotransferase [ALT] are found to be at abnormally high levels. The staging of the cancer can also be determined by abnormal elevated levels of calcium, which suggests that the cancer may have metastasised to the bones. In this case, a doctor should be prompted for a CT scan. Blood chemistry tests also assess the overall function of the kidneys and can allow the doctor to decide upon further radiological tests.