# US 4,399,003 A · Method and kit for diagnosing a patient's proneness to develop calcium oxalate kidney stones

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- Number: US 4,399,003 A
- Document ID: US4399003A
- Status: Granted
- Kind: A
- Application number: 06/256,777
- Filed: 1981-04-23
- Granted: 1983-08-16
- Earliest claimed: 1980-05-02
- Assignees: Yissum Research Development Company of the Hebrew University of Jerusalem
- Inventors: Sara Sarig; Nissim Garti; Francoise Tibika
- Web page: https://patentgrep.com/patent/US4399003A

## CPC

- G01N 33/84: involving inorganic compounds or pH
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A method is provided for diagnosing a patient's proneness to develop kidney tones of the calcium oxalate type, which comprises forming an aqueous reaction medium comprising from about 5 to about 20% by volume of a sample of the patient's urine, said medium having an ionic strength of from about 0.01 to about 0.1 and containing calcium ions at a concentration of from about 1 to about 5 mM/l and oxalate ions at a concentration of from about 1 to about 7 mM/l; measuring by means of a calcium ion-specific electrode the rate of decrease of the calcium ion concentration and comparing the thus measured rate with the corresponding rate determined with a reference sample of normal urine. A kit for carrying out the above method is also provided.

## Claims

### Claim 1

A method of diagnosing a patient's proneness to develop kidney stones of the calcium oxalate type, which comprises forming an aqueous reaction medium comprising from about 5 to about 20% by volume of a sample of the patient's urine, said medium having an ionic strength of from about 0.01 to about 0.1 and containing calcium ions at a concentration of from about 1 to about 5 mM/l and oxalate ions at a concentration of from about 1 to about 7 mM/l; measuring by means of a calcium ion-specific electrode the rate of decrease of the calcium ion concentration and comparing the thus measured rate with the corresponding rate determined with a reference sample of normal urine, as herein defined.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the reaction medium comprises from about 7.5 to about 15% by volume of the sample of the urine.

### Claim 3 (depends on 1)

A method according to claim 1, wherein the concentration of calcium ions in the reaction medium is from about 1.5 to about 3 mM/l.

### Claim 4 (depends on 1)

A method according to claim 1, wherein the concentration of oxalate ions in the reaction medium is from about 2 to about 4.5 mM/l.

### Claim 5 (depends on 1)

A method according to claim 1, wherein the reaction medium is formed by admixing a first aqueous solution comprising the calcium ions, other ions providing for the required ionic strength and the sample of the patient's urine, with a second aqueous solution containing the required concentration of oxalate ions.

### Claim 6 (depends on 5)

A method according to claim 5, wherein equal volumes of said first and said second solutions are admixed.

### Claim 7 (depends on 5)

A method according to claim 5, wherein said first solution consists of from about 60 to about 90% by volume of synthetic urine, as herein defined, and from about 10 to about 40% by volume of the sample of the patient's urine.

### Claim 8 (depends on 1)

A method according to claim 1, wherein the oxalate ions are derived from sodium oxalate.

### Claim 9 (depends on 1)

A method according to claim 1, wherein the normal urine used as a reference sample is synthetic urine as herein defined, to which were added 100 ppm. of poly-L-glutamic acid sodium salt of molecular weight above 5000.

### Claim 10 (depends on 1)

A method according to claim 1, which is carried out at a temperature of 25.degree. C.

### Claim 11 (depends on 1)

A kit for carrying out the method according to claim 1, said kit comprising packaged synthetic urine solution and packaged aqueous sodium oxalate solution, and further comprising a calcium ion-specific electrode and a reference electrode.