Diuretic Screening

Diuretic medications are used to artificially elevate the urination rate. Several types of diuretics can be used increase water excretion through distinct mechanisms.

The reference range value for urine diuretic screening is a negative test result.

The following are sought in a qualitative diuretic screening: metolazone, hydroflumethiazide, hydrochlorothiazide, furosemide, chlorthalidone, chlorothiazide, bumetanide, and benzthiazide.

The purpose of diuretic screening is to confirm diuretic usage in persons known or suspected to have used diuretics.

Urine is the specimen type to be collected.

A 10-mL aliquot of spot or random urine should be collected in a plastic container. No preservative should be used, and the specimen should be refrigerated during transport.

A minimum volume of 2 mL is required.

Only urine is acceptable; other specimens are rejected. Specimens can be accepted either warm or cold.

To ensure specimen stability, refrigerated urine (preferred) cannot be stored for more than 14 days, ambient urine for more than 72 hours, and frozen urine for more than 4,230 hours.

Description

Diuretic medications are used to artificially elevate the urination rate. Several types of diuretics can be used increase water excretion through distinct mechanisms.

Indications/Applications

Diuretics are used in the treatment of heart failure, liver cirrhosis, hypertension, and certain kidney diseases. Some diuretics (eg, acetazolamide) are used to make the urine more alkaline and can be efficacious for increasing the excretion of substances such as aspirin in cases of poisoning or overdose. Individuals with eating disorders, especially those with bulimia, often abuse diuretics in attempts at weight loss.

Some diuretics (thiazides and loop diuretics in particular) have antihypertensive actions that are independent of the diuretic effects. The blood pressure reduction is due to other mechanisms and is not attributable to decreased blood volume resulting from increased urine production.

The following are classes of diuretics:

• Thiazide-type diuretics

• Loop diuretics

• Osmotic diuretics

• Potassium-sparing diuretics

• Carbonic anhydrase inhibitors

Considerations

If the individual being screened is suspected of surreptitious use of a diuretic, an observed specimen collection is advised. ^[1]  Analyzing results from 2014-2017, a study by Aguilar-Navarro et al reported that tests run on athletes by the World Anti-Doping Agency revealed that diuretics and masking agents tended to be used more commonly in boxing, wrestling, taekwondo, judo, shooting, and gymnastics than in other sports. ^[2]