Diagnosis of Glomerulonephritis
Various investigations may be suggested if glomerulonephritis is suspected. These may include:

Testing the urine for blood and protein - this can be done using a dipstick in the clinic. You may also be asked to collect all of the urine that you produce over a 24-hour period to measure the exact amount of protein present.
A blood test to measure creatinine level - creatinine is a waste product produced by the muscles that is usually passed out in urine. Levels of creatinine in the blood rise if the kidneys are not working properly. The creatinine result can also be used to calculate the estimated glomerular filtration rate (eGFR). This gives a good measure of how well the kidneys are working.

A blood test to measure urea and electrolytes - these are usually measured at the same time as creatinine. Urea is another waste product, the levels of which rise in the blood if the kidneys are not working normally. Electrolytes include salts in the blood, such as sodium and potassium, the levels of which can be affected by kidney damage.

Levels of protein and albumin (a type of protein) can also be measured with blood tests. Blood protein levels will be low in nephrotic syndrome.
A blood test to check for anaemia.

Tests to look for the cause of glomerulonephritis - for example:
Tests to look for streptococcal infection, which may include a throat swab, a skin swab or a blood test to look for signs of the infection in the blood.

Tests to look for SLE, which may include a blood test to look for signs of this.

Chest X-ray - this may be suggested if you have any breathing problems.

Ultrasound scan of the kidneys - this can give information about the size of your kidneys, any blockages, etc.

A kidney biopsy - during a kidney biopsy, a small sample of tissue is taken from a kidney. The tissue can be examined under a microscope in the laboratory to give information about the cause of glomerulonephritis. Local anaesthetic is used to numb the area first and an ultrasound scan is used for guidance. A small needle is then passed through the skin to take the sample of tissue.