Renal colic is usually caused from an obstructing stone along the ureter. Some of the patients present with a high level of creatinin in the blood, even though there is a normal functioning contralateral kidney. Furthermore creatinin is not an ideal marker for renal function during acute changes.

Several works have shown that modern urinary markers such as NGAL (neutrophil gelatinase-associated lipocalin), KIM-1 (Kidney Injury Molecule-1) and others rise earlier and are much more sensitive for kidney insult. There is a lack of research on their role in acute kidney obstruction

The study population will include 100 men and women that will be recruited during the upcoming year, with a follow up of up to 3 months.

The study population will be divided into 2 groups:

1. The stone group: about 80 patients, aged 18-65, with normal creatinine for the past year that presented in our ER because of renal colic, and their imaging shows a ureteral stone.
2. The non-stone group: about 20 patients that present in our department for elective surgery not related to stones or bladder outlet obstruction.

The stone group:

---------------- In the ER the patients will be examined, undergo blood and urine workup and imaging as usual. If they are applicable according to our inclusion and exclusion criteria and admitted and they will be included in our stone group. After signing an informed consent, either as patients with a ureteral stone and normal creatinine or as patients with a ureteral stone and an abnormal creatinine, Their urine sample will be sent for the urinary markers: NGAL, KIM-1, ENdothelin and Cystatin C.

At this point it will be decided to admit or discharge them according to their clinical imaging and laboratory findings, as acceptable. The admitted patients will be followed for 48 with additional blood and urine tests.

The admitted patients that will undergo renal drainage will be a specific subgroup in which a selective urine test will be taken from the drained kidney

The non stone group:

-------------------- These are our control group from which we will take a single blood and urine test before their elective surgery.

Inclusion Criteria for stone group:

• no known kidney disease
• turned to the ER due to renal colic
• imaging demonstrates a partially or totally obstructing ureteral stone

Inclusion Criteria for non stone group:

• turned to the urology department for ambulatory surgery: hydrocelectomy, varicocelectomy, stress incontinence repair,circumcision,cystoscopy

Exclusion Criteria:

• patients with stones in the contralateral ureter
• patients who underwent renal surgery
• patients who took NSAID's (nonsteroidal antiinflammatory drugs) in the past week before presentation
• patients woth anatomical defects in the kidneys

100 men and women - 80 presented in the ER with a unilateral ureteral stone and 20 presented for ambulatory surgery not related to urinary stones or bladder outlet obstruction