vagreys
02-07-2007, 08:52 PM
Note: This is not medical advice, but merely a compilation of lab reference values based on the summaries of various studies and accepted values used by veterinarians I know. Please discuss all lab results with your veterinarian. If someone can come up with a more pleasing presentation of the reference values (I couldn't figure out how to create a table), please let me know.
In recent centuries, Greyhounds have gradually become sprinters. For thousands of years before that, though, they were long-distance runners, and their bodies and blood evolved to support the demands of extreme running. It is in their genetic makeup, and even in hounds that have never run, the differences are evident. Blood pressure runs higher, respirations and pulse run lower, and blood components are skewed. As a result, Greyhound blood lab results sometimes lead to misdiagnosis by those unfamiliar with Greyhounds.
Various studies have been conducted in the UK, the USA, and in Australia to establish reference ranges for retired racing Greyhounds, and while outlying values will always exist, reasonable references have been established. Here are some of the differences of which you need to be aware.
Red Cells. Greyhounds have about 1/3 again more red blood cells than other breeds. This makes them excellent blood donors, but it also means that anemia in Greyhounds is sometimes missed. It also means that a diagnosis of polycythemia in Greyhounds (over-production of red cells) is unlikely, unless the values are well above the Greyhound reference range. Red Blood Cell (RBC), Hemaglobin (Hgb), and Packed Cell Volume/Hematocrit (PCV/HCT) values are going to be higher than for other breeds. And a PCV that would be high-normal in most breeds should be considered anemic in a Greyhound.
White Cells. While many vets are familiar with Greyhounds as blood donors, fewer are aware that the White Blood Cell (WBC) count in Greyhounds is also different, and about half that of other breeds. This has caused many a wild goose chase for a phantom infection or cancer, where none may exist.
Platelets. Greyhound Platelet counts are less than half that of other breeds.
Total Protein. The albumin fraction of total protein in Greyhounds is the same as in other breeds, but the globulin fraction is lower. Total Protein (T.P.) in Greyhounds runs at the low end of normal for other breeds.
Creatinine. Greyhounds have a lot of lean muscle mass, and very little body fat. So, Greyhounds have higher creatinine levels, about 1.5 times higher than other breeds. By itself, an elevated creatinine level is not a basis for diagnosing renal disease/failure. BUN, BUN/Creatinine ratio, and urinalysis must be evaluated along with creatinine for other indications of renal disease.
Thyroid. Greyhound thyroid levels run much lower than other breeds - as low as 1/2 to 1/3 of other breeds. Hypothyroidism is sometimes misdiagnosed in Greyhounds, condemning them to a lifetime on unnecessary thyroid medication. Whole papers and books have been devoted to Greyhound thyroid function, but the bottom line is that, before a diagnosis of hypothyroidism is accepted, based on secondary factors, the basal T4, free T4 (fT4), and Thyroid Stimulating Hormone (TSH) need to be considered, together. Also, because Greyhound values are so low, the free T4 level should always be determined by equilibrium dialysis. Normal basal T4 levels run a little lower in older Greyhounds than in younger Greyhounds, which further compounds things. Thyroid levels also fluctuate and may be low for other reasons including illness and stress.
I have looked at summaries of reference values from several studies conducted the US, UK, and Australia. Here are accepted reference values for Greyhounds, as they are generally presented on lab reports to owners, followed by accepted reference values for other breeds.
Normal Reference Values for Greyhounds:
RBC - Red Blood Cells: 7.4 - 9.0
Hgb - Hemaglobin: 19.0 - 21.5
PCV - Packed Cell Volume: 55 - 65
WBC - White Blood Cells: 3.5 - 6.5
Platelets: 80,000 - 200,000
T.P. - Total Protein: 4.5 - 6.2
Globulin Fraction: 2.1 - 3.2
Creatinine: 0.8 - 1.7
T4 (younger Greyhounds): 0.7 - 3.6
T4 (older/retired Greyhounds): 0.5 - 3.6
fT4 and TSH reference ranges are the same as for other breeds.
Normal Reference Values for Other Breeds:
RBC - Red Blood Cells: 5.5 - 8.5
Hgb - Hemaglobin: 12.0 - 18.0
PCV - Packed Cell Volume: 37 - 55
WBC - White Blood Cells: 6.0 - 17.0
Platelets: 150,000 - 400,000
T.P. - Total Protein: 5.4 - 7.8
Globulin Fraction: 2.8 - 4.2
Creatinine: 0.0 - 1.0
T4: 1.8 - 3.6
fT4: 0.7 - 2.5
TSH - Thyroid Stimulating Hormone: .05 - .42
Sources:
C. G. Cuoto, DVM, "Why Is My Dog's Labwork Different From Yours?", Ohio State University School of Veterinary Medicine, 2005.
L. L. Blythe, A. M. Craig, J. R. Gannon, Care of the Racing Greyhound: A Guide for Trainers, Breeders and Veterinarians, Veterinary Practice Publishing, 1994.
W. Brewer, J. Steiss, E. Welles, J. Wright, "Hematologic & Serum Biochemical Reference Values in Retired Greyhounds," Compendium on Continuing Education, March 2000.
L. D. Carlson, J. M. Griffin, Dog Owner's Home Veterinary Handbook, 3rd Ed., Howell Reference Books, 1999.
M. Siegal, UC Davis Book of Dogs: The Complete Medical Reference Guide for Dogs and Puppies, Collins, 1995.
In recent centuries, Greyhounds have gradually become sprinters. For thousands of years before that, though, they were long-distance runners, and their bodies and blood evolved to support the demands of extreme running. It is in their genetic makeup, and even in hounds that have never run, the differences are evident. Blood pressure runs higher, respirations and pulse run lower, and blood components are skewed. As a result, Greyhound blood lab results sometimes lead to misdiagnosis by those unfamiliar with Greyhounds.
Various studies have been conducted in the UK, the USA, and in Australia to establish reference ranges for retired racing Greyhounds, and while outlying values will always exist, reasonable references have been established. Here are some of the differences of which you need to be aware.
Red Cells. Greyhounds have about 1/3 again more red blood cells than other breeds. This makes them excellent blood donors, but it also means that anemia in Greyhounds is sometimes missed. It also means that a diagnosis of polycythemia in Greyhounds (over-production of red cells) is unlikely, unless the values are well above the Greyhound reference range. Red Blood Cell (RBC), Hemaglobin (Hgb), and Packed Cell Volume/Hematocrit (PCV/HCT) values are going to be higher than for other breeds. And a PCV that would be high-normal in most breeds should be considered anemic in a Greyhound.
White Cells. While many vets are familiar with Greyhounds as blood donors, fewer are aware that the White Blood Cell (WBC) count in Greyhounds is also different, and about half that of other breeds. This has caused many a wild goose chase for a phantom infection or cancer, where none may exist.
Platelets. Greyhound Platelet counts are less than half that of other breeds.
Total Protein. The albumin fraction of total protein in Greyhounds is the same as in other breeds, but the globulin fraction is lower. Total Protein (T.P.) in Greyhounds runs at the low end of normal for other breeds.
Creatinine. Greyhounds have a lot of lean muscle mass, and very little body fat. So, Greyhounds have higher creatinine levels, about 1.5 times higher than other breeds. By itself, an elevated creatinine level is not a basis for diagnosing renal disease/failure. BUN, BUN/Creatinine ratio, and urinalysis must be evaluated along with creatinine for other indications of renal disease.
Thyroid. Greyhound thyroid levels run much lower than other breeds - as low as 1/2 to 1/3 of other breeds. Hypothyroidism is sometimes misdiagnosed in Greyhounds, condemning them to a lifetime on unnecessary thyroid medication. Whole papers and books have been devoted to Greyhound thyroid function, but the bottom line is that, before a diagnosis of hypothyroidism is accepted, based on secondary factors, the basal T4, free T4 (fT4), and Thyroid Stimulating Hormone (TSH) need to be considered, together. Also, because Greyhound values are so low, the free T4 level should always be determined by equilibrium dialysis. Normal basal T4 levels run a little lower in older Greyhounds than in younger Greyhounds, which further compounds things. Thyroid levels also fluctuate and may be low for other reasons including illness and stress.
I have looked at summaries of reference values from several studies conducted the US, UK, and Australia. Here are accepted reference values for Greyhounds, as they are generally presented on lab reports to owners, followed by accepted reference values for other breeds.
Normal Reference Values for Greyhounds:
RBC - Red Blood Cells: 7.4 - 9.0
Hgb - Hemaglobin: 19.0 - 21.5
PCV - Packed Cell Volume: 55 - 65
WBC - White Blood Cells: 3.5 - 6.5
Platelets: 80,000 - 200,000
T.P. - Total Protein: 4.5 - 6.2
Globulin Fraction: 2.1 - 3.2
Creatinine: 0.8 - 1.7
T4 (younger Greyhounds): 0.7 - 3.6
T4 (older/retired Greyhounds): 0.5 - 3.6
fT4 and TSH reference ranges are the same as for other breeds.
Normal Reference Values for Other Breeds:
RBC - Red Blood Cells: 5.5 - 8.5
Hgb - Hemaglobin: 12.0 - 18.0
PCV - Packed Cell Volume: 37 - 55
WBC - White Blood Cells: 6.0 - 17.0
Platelets: 150,000 - 400,000
T.P. - Total Protein: 5.4 - 7.8
Globulin Fraction: 2.8 - 4.2
Creatinine: 0.0 - 1.0
T4: 1.8 - 3.6
fT4: 0.7 - 2.5
TSH - Thyroid Stimulating Hormone: .05 - .42
Sources:
C. G. Cuoto, DVM, "Why Is My Dog's Labwork Different From Yours?", Ohio State University School of Veterinary Medicine, 2005.
L. L. Blythe, A. M. Craig, J. R. Gannon, Care of the Racing Greyhound: A Guide for Trainers, Breeders and Veterinarians, Veterinary Practice Publishing, 1994.
W. Brewer, J. Steiss, E. Welles, J. Wright, "Hematologic & Serum Biochemical Reference Values in Retired Greyhounds," Compendium on Continuing Education, March 2000.
L. D. Carlson, J. M. Griffin, Dog Owner's Home Veterinary Handbook, 3rd Ed., Howell Reference Books, 1999.
M. Siegal, UC Davis Book of Dogs: The Complete Medical Reference Guide for Dogs and Puppies, Collins, 1995.