Approximately seven million of us have health insurance in the UK, for the most part it's provided by employers as a benefit. Consequently, most people take health insurance for granted and don't really look at the policy documents. That means that they don't really know what's covered, and what's not. If you think that health insurance will cover all your health costs, you're unfortunately wrong.

Health insurance is very particular in its purpose and is fine for curable, short-term health problems, and for allowing policyholders to bypass the NHS queues and get straight through to the consultants to receive quality care in a much faster time. However, there are many other treatments and situations which do not fall within the scope of the policy.

Before you read on, we should advise you that every policy is different and you really need to read your own documents to get the full picture. However, this article will give you some very good pointers on what to look out for.

Chronic conditions

If you fall ill and it turns out that the illness can be cured in the short-term, it's called acute' and you're covered. If, however, your problem is incurable or, even with treatment, it will last for a long time, then it will be classed as chronic' and your policy will not cover you.

It's the line between acute' and chronic' that causes conflict between insurer and policyholders. Diabetes and asthma for example are chronic they are not curable and they stay with you for the rest of your life. Some types of cancer cannot be so easily classified. The doctors may decide that the cancer is curable, but then the illness could worsen and the diagnosis could be changed to incurable. This means that while the illness is considered curable, then you can make the most of your cover, but if the diagnosis changes to incurable, your cover will be lost. Insurance companies reserve the right to reclassify an illness from acute to chronic during treatment.

Long-term treatment

Long-term treatment is a definite no-no. But check your policy documents first to see their definition of long-term. It may be that the insurer will pay for 10 months, so if it's a 12 month treatment, you will need to pay for the final 2 months yourself.

Preventative medicine

Health insurance covers the treatment and cure of conditions, it cannot be used to pay for preventative treatment.

What counts as being preventative is another grey area. For example, the drug Herceptin is used in the early stages of breast cancer, and research shows that Herceptin can reduce the chance of the cancer returning by 50% for women who have an aggressive form of the cancer called HER2'. Some insurance companies call it preventative, some call it treatment:

Norwich Union, WPA, BUPA and Standard Life Healthcare will pay