learn about your tests in plain-English

It can feel awkward to hand over a jar of your bodily waste to a collector. You may think to yourself, why can’t they just take a blood sample? But urine tests can tell us a lot about our health that blood can’t.

(Also – don’t feel awkward, your collector is a trained health professional and they’re not fazed by a bit of urine.)

What are urine tests used for?

Urine tests can be used for a whole range of diagnoses. From confirming a pregnancy to diagnosing an infection such as a UTI or an STI, checking kidney function, monitoring diseases such as diabetes and bladder cancer or monitoring drug use (for legal purposes or a pre-employment screening).

Urine is produced in your kidneys and passed through the urinary tract (ureters, bladder and urethra) before being expelled from the body. It’s mostly water (about 99%) but the remaining 1% is made up of urea, uric acid, ammonia, hormones, dead blood cells, proteins, salts and minerals, and toxins. It’s a waste product – your body getting rid of chemicals it doesn’t need. And that’s why urine tests are so useful; in many cases we can learn as much about a person’s health from what the body expels as what it holds onto.

A person with kidney disease, for example, will have both urine tests and blood tests to monitor their condition. The urine is tested for albumin, a type of protein. Your body needs protein, so having high levels in your urine may mean that your kidneys are not filtering your blood well enough. The blood is tested for creatinine, which comes from muscle tissue. It’s a waste product but when the kidneys are damaged, they have trouble removing creatinine from your blood.

Collection

Generally, it doesn’t matter what time of day you collect a urine sample, but there are occasional exceptions. Your doctor may, for example, request a first morning sample because the urine is more concentrated and therefore it is more likely to show up any abnormalities.  Or if the doctor is looking for glucose in the urine they may ask you to collect a sample after a meal.

You will probably be asked for a “mid-stream” sample. Urine is naturally sterile so if a test shows up bacteria this can be a sign of infection. By taking a sample from the middle of the stream you are reducing the likelihood of contamination from bacteria and cells from the surrounding skin. This is important – contamination due to improper collection can mean having to provide a second sample or even result in unnecessary treatment.

What happens to your urine once it’s in the lab?

Luckily for lab staff technology has improved a lot over the years when it comes to urine testing. In Medieval Europe doctors would observe the smell, consistency and even taste of urine to diagnose their patients.

These days analysis is a bit more scientific. For a UTI, for example, the first step usually involves your doctor carrying out a point of care test, whereby they dip a specially treated strip into a urine sample.

The strip will change colour depending on the diagnosis. If it detects white blood cells, blood or chemicals called nitrites, infection is likely. The sample is then sent to a lab for further testing. In the lab a scientist analyses the sample to confirm the presence of white blood cells and bacteria. They can also test it to work out which antibiotic is most likely to be effective (an important step in combating antibiotic resistance).

And whilst your lab technician isn’t tasting your sample, the Medieval doctors weren’t entirely wrong. A strong odour, for example, could be a sign of a urinary tract infection whilst a sweet smell could indicate diabetes. Cloudy urine could be a result of infection whilst pinkish coloured urine may mean there’s blood present.

The post Everything you need to know about urine tests first appeared on Know Pathology Know Healthcare.

But finding out what food someone is allergic to in the first place can still be tricky.

Allergy testing can be a complex process; it may include a specific IgE blood test to look for antibodies in the bloodstream linked to an allergic response.

Skin prick testing may also be used and involves scratching the surface of the skin and applying a small amount of various allergens then monitoring any reaction.

An oral challenge test, where certain foods are consumed and symptoms monitored, might also be needed to confirm an allergy.

However, some recent research in Japan might point towards a simpler, less invasive avenue for allergy testing.

Researchers at the University of Tokyo tested the urine of mice with allergies to egg and milk. They wanted to see if urine testing could help to pick up an allergy and determine the level of severity.

They found that the compound prostaglandin D2 metabolite (PGDM) was present in high levels in the urine of allergic mice, and higher levels of PGDM were consistent with a more severe allergy.

The team also tested human urine samples comparing the urine of patients with and without allergies.

Importantly the raised levels of PGDM were only found in people with food allergies, not healthy volunteers or those with other allergic conditions such as asthma, allergic rhinitis (hay fever), and atopic dermatitis.

It is early days still, but this finding could be a useful step in streamlining diagnosis of allergies, particularly in young children who may find the process of skin prick testing and oral challenges distressing.

Food allergies affect 1-2% of adults and 4-8% of children under 5 in Australia. While fantastic progress has been made recently in search of a cure, early diagnosis remains important to ensure that precautions can be taken to minimise the risk of exposure to a potentially life-threatening food.

The post New research is putting the ‘pee’ in peanut allergy testing first appeared on Know Pathology Know Healthcare.