Chloride

Blood chloride testing is often ordered, along with other electrolytes, as part of a regular physical to screen for a variety of conditions. These tests may also be ordered to help diagnose the cause of signs and symptoms such as prolonged vomiting, diarrhea, weakness, and respiratory distress. If an electrolyte imbalance is detected, the doctor will look for and address the disease, condition, or medication causing the imbalance and may order electrolyte testing at regular intervals to monitor the effectiveness of treatment. If an acid-base imbalance is suspected, the doctor may also order blood gas tests to further evaluate the severity and cause of the imbalance.

In persons with too much base, urine chloride measurements can tell the doctor whether the cause is loss of salt (in cases of dehydration, vomiting, or use of diuretics, where urine chloride would be very low) or an excess of certain hormones such as cortisol or aldosterone (where urine chloride would be high). Urine tests for chloride are also used, along with sodium, to monitor persons put on a low-salt diet. If sodium and chloride levels are high, the doctor knows that the patient is not following the diet.

The blood chloride test is almost never ordered by itself. It is usually ordered as part of an electrolyte panel, a basic metabolic panel, or a comprehensive metabolic panel, which are ordered frequently as part of a routine physical. Chloride may be ordered when acidosis or alkalosis is suspected or you have an acute condition with symptoms that may include the following:

• Prolonged vomiting and/or diarrhea
• Weakness, fatigue
• Respiratory distress

Some of these tests may be ordered at regular intervals when a patient has a disease or condition or is taking a medication that can cause an electrolyte imbalance. Electrolyte panels or basic metabolic panels are commonly used to monitor treatment of certain problems, including high blood pressure (hypertension), heart failure, and liver and kidney disease.

A urine chloride test may be performed along with a blood or urine sodium when evaluating the cause of low or high blood chloride levels. The doctor will look at whether the chloride measurement changes mirror those of the sodium. This helps the doctor determine if there is also an acid-base imbalance and helps to guide treatment.

Increased levels of blood chloride (called hyperchloremia) usually indicate dehydration, but can also occur with other problems that cause high blood sodium, such as Cushing's syndrome or kidney disease. Hyperchloremia also occurs when too much base is lost from the body (producing metabolic acidosis) or when a person hyperventilates (causing respiratory alkalosis).

Decreased levels of blood chloride (called hypochloremia) occur with any disorder that causes low blood sodium. Hypochloremia also occurs with prolonged vomiting or gastric suction, emphysema or other chronic lung diseases (causing respiratory acidosis), and with loss of acid from the body (called metabolic alkalosis).

Drugs that affect sodium blood levels will also cause changes in chloride. In addition, swallowing large amounts of baking soda or substantially more than the recommended dosage of antacids can also cause low chloride.

Sim. A Food and Nutrition Board do Instituto de Medicina dos Estados Unidos recomenda que adolescentes e adultos com idade entre 14 e 50 anos consumam 2,3 g/dia. As recomendações variam de acordo com a idade, sexo e outros fatores. Por exemplo, gestantes e lactantes precisam de maiores quantidades, enquanto crianças e adultos mais velhos precisam de quantidades menores. O cloreto está prontamente disponível nos alimentos e a maioria dos americanos, provavelmente, consome mais do que o necessário, na forma de sal de mesa e no sal dos alimentos industrializados. É também encontrado em muitos vegetais e alimentos como algas, centeio, tomate, alface, aipo e azeitonas.