Older Horse Lab Tests: Kidney, Liver and Thyroid

Blood tests in an older horse can help a vet look at the kidneys, liver and thyroid when the horse is losing weight or has a poor coat. They show how organs are working, but they rarely give the whole answer alone. A registered veterinarian reads the results with the horse's teeth, feed, worms and general check-up.

Why does an older horse lose weight or condition?

Weight loss in an ageing horse has many possible causes, and organ disease is only one of them. Worn or painful teeth can make chewing hard, so feed is wasted. Worms, poor-quality feed, long-standing pain, infections and hormone changes can all play a part.

A vet usually starts with a physical examination and a look in the mouth, then uses blood tests to narrow the list. A horse that stops eating, turns suddenly dull or shows signs of colic needs a vet at once. Do not wait for lab results in that case.

Tell your vet what you have noticed: how the horse eats and drinks, how its droppings look, whether it stands apart from the herd and how long the coat has looked different. This history helps the vet choose the right tests, and it is often as useful as the numbers themselves.

What does a blood count add?

A Complete Blood Count (CBC) gives a first look at red cells, white cells and platelets. Fewer red cells, called anaemia, may indicate long-term illness or blood loss. White cell changes may point to infection or inflammation. The count does not name the cause, but it tells your vet where to look next.

What can the kidney test show?

Urea and creatinine are waste products that healthy kidneys filter out of the blood. In a Kidney Function Test (KFT), higher levels may indicate that the kidneys are not clearing them well. Dehydration can raise them too, so your vet considers how much the horse has been drinking, the weather and the workload.

A horse with kidney trouble may lose weight, eat less and look dull. Your vet may add a urine test to get a fuller picture.

What can the liver test show?

The liver helps to process feed, make proteins and clear waste. A Liver Function Test (LFT) measures enzymes and other substances in the blood that may change when liver cells are damaged or the flow of bile is blocked. Yellow gums or eyes, weight loss and a dull look can go with liver trouble.

The liver can cope with a lot of damage before signs appear, so a blood check may pick up a problem early. The result is a pointer, not a diagnosis. Your vet may repeat it or suggest a scan.

Why is the thyroid test read with care?

The thyroid gland sits in the neck and makes thyroxine, or T4, a hormone that helps control how the body uses energy. The Equine T4 (Thyroxine) measures T4 in the blood. A low T4 in a horse does not prove thyroid disease. Illness elsewhere in the body, low feed intake and some medicines can lower T4, and true thyroid disease is thought to be uncommon in horses.

For this reason vets avoid judging from one number. A poor or unusually long coat has other possible causes too, including other hormone problems, so your vet may suggest different tests if T4 does not explain the signs.

Do repeat tests help?

Often they do. An older horse's results are most useful when compared over time, because one result is a snapshot and two or three show a direction. A set taken now can also serve as a starting point for later checks, so keep every report together and show them all to your vet.

The Horse Health Check Panel groups routine checks for horses. The exact list is confirmed when you book, and your vet can add or remove tests to suit the horse.

Read next

For a closer look at why T4 can mislead, read Thyroid Testing in Horses: What Equine T4 Can and Cannot Show. If your horse lives outside Bhopal, Sending Samples to a Bhopal Vet Lab from Other MP Districts explains how samples reach the lab.

Testing in Bhopal

Older horses often hate being moved, so ask your vet to take the blood at the stable. In Bhopal the lab can collect the sample free of charge, and the lab confirms the method, sample needs and reporting time when you book. Call or WhatsApp +91 88175 01118; the lab is at C-200, C Sector, Shahpura, Bhopal. From other districts, samples can come by courier, bus parcel or through your vet.