*4.1.2.3 Examination of blood, urine, seminal plasma, and the sperm-rich phase*

In case of canine BPH, *examination of blood* parameters usually reveals normal findings, whereas *examination of the urine* in some cases reveals hematuria [34, 38]. *Seminal plasma* and *prostate secretions* often contain erythrocytes [40], *spermatozoa* often show a decrease in motility and an increase in morphological abnormalities [19, 39, 40].

A *bacteriological examination* of prostate secretion, urine, and semen is often negative and may give a hint, however, cannot be used solely for diagnosis [38]. Prostate secretions can be obtained by digital-rectal massaging of the gland, while a urinary catheter is placed at the site of the pars disseminata. The secretions can be aspirated, provided the urinary bladder was emptied and flushed before; they can be examined cytologically and bacteriologically [19]. Collection of more prostate gland epithelial cells is possible by use of the urethra-brush method. The brush is introduced in the urethra while hidden in a plastic catheter; at the site of the prostate gland, the brush is pushed forward several times and then sterile retracted inside the catheter and outside the urethra. The brush and the collected fluid are deposited in sterile sodium chloride solution and centrifuged, the pellet can be examined cytologically and bacteriologically [40].

In dogs, the final diagnosis BPH can only be made by use of fine needle aspiration (FNA); this method should be performed when the dog is sedated and received analgesia. The FNA is done transcutaneously under sonographical control [8, 19]. However, even though providing the final diagnosis, this method is mostly not necessary. The cytologically obtained results correlate well with histopathology. Only for differentiation between chronical prostatitis and prostate gland carcinoma, FNA or biopsy must be performed [66, 72–74].

Measurement of the canine prostate-specificesterase (CPSE) can be helpful. The concentration of this enzyme in the blood is significantly increased in case of canine BPH and other diseases [29, 33, 48, 75–78]. Unfortunately, it is not possible to differentiate between BPH, prostatitis, and neoplasia, and the reference values for healthy dogs are variable in the literature [48, 75, 77]. The secretion of the CPSE is age-dependent in dogs, therefore, reference values must be critically considered. The diagnosis BPH should not be solely based on measurement of the CPSE. In one study, a combination of clinical symptoms, CPSE measurement, and calculation of the prostate volume (real volume/estimated volume = V ratio) were evaluated. The clinical BPH coincided with a V-ratio of >2.5 and a CPSE concentration of > 90 ng/ml; the sensitivity was 85% and the specificity 72% [48]. Meanwhile, a commercial assay is available (Odelis® CPSE, Bio Veto Test, Nice, France) and another study revealed a sensitivity of 97.1% and a specificity of 92.1% [79].
