Kidneys and electrolytes
Chloride
A salt in the blood that, together with sodium, regulates fluid balance and acidity; usually assessed together with other salts.
Everything about this testWhat it measures
Chloride is a negatively charged salt (electrolyte) that mainly enters the body through table salt (sodium chloride). Together with sodium, potassium and bicarbonate, it regulates the amount of fluid in the body and the acidity of the blood. The kidneys excrete excess chloride in the urine. Chloride usually follows sodium: if sodium rises or falls, chloride often does the same. A chloride value on its own therefore says little; its meaning comes from the combination with sodium and bicarbonate.
- Disturbance of fluid balance, such as dehydration
- Disturbance of acid-base balance (metabolic acidosis or alkalosis), together with bicarbonate
- Loss of salts due to prolonged vomiting or diarrhea
High
According to the Dutch Society for Clinical Chemistry (NVKC), a raised chloride mainly occurs with dehydration, for example from drinking too little, sweating or fever; sodium is then usually raised too. It can also fit metabolic acidosis (the blood is too acidic because the body loses base), for example with prolonged diarrhea or a kidney problem; bicarbonate is then low. Rapid breathing (hyperventilation) can also slightly raise chloride. A slightly raised value with normal other salts usually has no meaning.
Low
According to the Dutch Society for Clinical Chemistry (NVKC), a low chloride often goes together with a low sodium. Loss of chloride mainly occurs with prolonged vomiting, because stomach acid contains chloride. It can also fit metabolic alkalosis (the blood is too alkaline), for example with water pills or prolonged vomiting; bicarbonate is then raised. Chloride can also be low with chronic lung diseases. Symptoms usually come from the cause and not from the chloride itself.
If your result is abnormal
With an abnormal chloride, the GP assesses the value together with sodium, potassium, bicarbonate, creatinine, fluid intake and medicines, and repeats the measurement if there is no clear explanation. If a disturbed acid-base balance is suspected, further testing may follow, sometimes in hospital.
Reliability
The chloride measurement is accurate, but according to the Dutch Society for Clinical Chemistry (NVKC), a value on its own can only be properly interpreted together with sodium, potassium, bicarbonate and the person's situation. The measurement is mainly meaningful in people who are ill or when testing acid-base balance. Small abnormalities in someone without symptoms are often temporary and without meaning.
Limitations
- Drinking too little or a lot, sweating, vomiting and diarrhea temporarily shift the value.
- Water pills, laxatives and IV fluids containing salt affect chloride.
- Reference values differ slightly between laboratories and measurement methods.
How common is this
There are no Dutch figures on how often an abnormal chloride occurs. In healthy adults without symptoms or medicines, a clearly abnormal value is unusual. Abnormalities are mainly seen with dehydration, prolonged vomiting or diarrhea and in people who are ill in hospital.
Who is this useful for
The result says the most with prolonged vomiting or diarrhea, dehydration, use of water pills or when a disturbed acid-base balance is suspected, always together with sodium, potassium and bicarbonate. Endurance athletes who sweat a lot can have small shifts. In healthy adults without symptoms, the result is almost always normal.
Downsides and risks
- A slightly abnormal chloride without symptoms usually has no meaning, but can cause unnecessary worry if it is read separately from the other salts.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results