Objective: To establish reference range values for synovial fluid from clinically normal New World camelids.
Animals: 15 llamas and 15 alpacas.
Procedure: Llamas and alpacas were anesthetized with an IM injection of a xylazine hydrochloride, butorphanol tartrate, and ketamine hydrochloride combination. Synovial fluid (1 to 2 ml) was obtained by aseptic arthrocentesis from the radiocarpal and tarsocrural joints. Synovial fluid evaluation included determination of total nucleated cell count (NCC), absolute number and percentage of polymorphonuclear (PMN) and mononuclear leukocytes, total protein, and specific gravity.
Results: Synovial fluid evaluation revealed a total NCC of 100 to 1,400 cells/microl (mean +/- SD, 394.8+/-356.2 cells/microl; 95% confidence interval [CI], 295.2 to 494.6 cells/microl). Mononuclear leukocytes were the predominant cell type with lymphocytes, composing 50 to 90% (mean, 75.6+/-172%; 95% CI, 70.8 to 80.4%) of the mononuclear leukocytes. Approximately 0 to 12% (mean, 1.3+/-2.9%; 95% CI, 0.49 to 2.11%) of the cells were PMN leukocytes. Total protein concentrations ranged from 2.0 to 3.8 g/dl (mean, 2.54+/-0.29 g/dl; 95% CI, 2.46 to 2.62 g/dl); the specific gravity ranged between 1.010 and 1.026 (mean, 1.017+/-0.003; 95% CI, 1.016 to 1.018).
Conclusion and clinical relevance: In llamas and alpacas, significant differences do not exist between species or between limbs (left vs right) or joints (radiocarpal vs tarsocrural) for synovial fluid values. Total NCC and absolute number and percentage of PMN and mononuclear leukocyte are similar to those of other ruminants and horses. However, synovial fluid total protein concentrations in New World camelids are high, compared with other domestic species.