Blood Count and Urinalysis for Dogs
An estimate will also be made of the total number of white blood cells (WBC) in the sample. White blood cells include eosinophils (cells that fight parasite infestations and are involved in allergies), and cells that fight infections or cellular invaders, including neutrophils, lymphocytes, basophils, and monocytes. The number of white blood cells such as lymphocytes may be increased in dogs with certain cancers, as well. Normally, white blood cell counts rise with bacterial infections, but if the infection is winning the battle, counts may be lower than expected. Viruses may also lower the white blood cell count.
Platelets are cells that assist in clotting and coagulation. An estimate of their numbers is also made from a blood sample on a slide examined under a microscope. Platelets can be low in number in dogs with certain immune disorders, some cancers, and bleeding disorders. Some breeds, such as Cavalier King Charles Spaniels, can have platelet anomalies that cause their numbers to be low.
Urinalysis involves looking at a urine specimen. Urine samples may be collected as a “free catch” when the dog is voiding or by using a catheter or a needle inserted directly into the bladder. The last two methods are much better if an infection is suspected, because the sample collected is sterile and any bacteria cultured from it is likely to be the culprit.
The urine is checked for certain components, such as glucose and pH. Concentration and the presence of any cells are also evaluated. Some of this is done with a specially coated test strip that gives a range for results and some is done with special instruments.
Dilute urine may mean kidney problems or increased drinking. Concentrated urine could mean dehydration or liver or kidney problems.
The urine is checked for glucose, indicating diabetes mellitus, and for protein, indicating kidney damage. The pH will tell if the urine is acidic or alkaline, which can be influenced by diet and may cause bladder crystals or stones to form.
The urine is also spun in a centrifuge and the cells collected and examined. The presence of red blood cells or white blood cells may indicate infections or damage to the urinary tract. Crystals suggest stone formation. Bacteria can indicate infection, in which case the sample may also be cultured to look for bacterial infections.