Raised Alkaline Phosphatase (ALP)

The substance called ALP is found in our body mostly in the liver and the bones. When this value comes back high in a blood test, the body is in effect telling us that there is “intense activity” or a “blockage” in one of these two organs.

The difference between a young patient and an older patient, and the meaning of this rise, can be summarised as follows:

1. Raised ALP in Young Patients

In young people this is usually nothing to fear and is most often temporary.

• The growth period (the most common cause): Because young people’s bones are still growing and lengthening, bone cells work very fast. This fast work naturally shows up as a high ALP in the blood test. In other words, it is not a disease but a sign of growth.
• Healing fractures: If a bone has recently been broken or cracked, the bone raises this value while it repairs itself.

2. Raised ALP in Older Patients

Because bone growth has stopped in older people, this rise usually points to a condition that needs follow-up and treatment:

• Hidden vitamin D deficiency: As we age, the body can no longer make or absorb vitamin D as it used to. As the bones are left short of the vitamin and weaken, they start producing more ALP to make up for the deficiency.
• Bile duct blockages: If there is an obstruction (a blockage) such as a stone, sludge or a narrowing in the ducts through which the bile made by the liver should flow, the ALP level in the blood rises quickly.
• Medicines: The blood pressure, cholesterol, painkiller or rheumatism medicines used by older patients can strain the liver somewhat and raise this value.
• Changes in bone structure: Certain specific bone diseases seen in old age that distort the shape or quality of bone (such as Paget’s disease) can raise ALP to very high levels.

How Do Doctors Find the Source?

To tell whether this rise comes from the bone or the liver, your doctor looks at a very simple additional blood test called GGT:

• If the GGT test is normal: The problem is related to the bones (vitamin D deficiency and the like).
• If the GGT test is also high: The problem is related to the liver or the bile ducts.

GGT (gamma-glutamyl transferase) is a type of protein (an enzyme) found in our body mostly in the liver and the bile ducts. You can think of a high GGT in the blood as a “call for help” or an “early warning signal” sent to you by your liver or bile ducts.

GGT is one of the most sensitive messengers in the liver. When liver cells are exposed to even the slightest stress, strain or irritation, they reveal it straight away by leaking GGT into the blood.

Why Does GGT Rise? (The Most Common Causes)

A raised GGT is triggered by conditions that strain the liver or make the flow of bile difficult:

• Fatty liver: Today the most common cause of a raised GGT. When more fat than normal builds up in the liver, the cells come under pressure and release GGT into the blood.
• Medicines and supplements: Regularly used blood pressure, cholesterol and neurology medicines, or frequently taken painkillers and antibiotics, can strain the liver. Even some innocent-looking herbal teas and supplements can make GGT shoot up.
• Slowed bile flow (blockage): The bile made by the liver flows through small ducts to the gallbladder and the intestine. If there is slowing or obstruction in these ducts because of a stone, sludge or inflammation, the GGT level rises quickly.
• Alcohol use: GGT is remarkably sensitive to alcohol. Regular or heavy drinking puts liver cells under direct stress and raises GGT.
• Hepatitis (inflammation of the liver): In hepatitis caused by viruses (such as hepatitis A, B and C), or in conditions where the immune system attacks its own liver, GGT rises because the cells are damaged.

What Is the Relationship Between ALP and GGT?

When a raised ALP and GGT are assessed together, they make an excellent map for doctors:

If the blood test shows…	What does it mean?
Both ALP and GGT are high	The source of the problem is definitely the liver or the bile ducts.
ALP is high but GGT is normal	Your liver is safe; the problem is most likely of bone origin (vitamin D deficiency, bone growth and the like).

What Is Done When GGT Comes Back High?

A raised GGT on its own does not mean a frightening disease; it is simply a “look after your liver” message. Doctors usually do the following:

• They look at other values: To see the state of the liver fully, they check ALT, AST and bilirubin.
• They arrange imaging: A whole-abdomen ultrasound is requested to see whether there are stones in the gallbladder or fat in the liver.
• They recommend lifestyle changes: If there is no serious blockage, improving the diet, balancing weight, stopping alcohol and stopping unnecessary medicines bring GGT back to its normal level within a short time.