Page 820 - Small Animal Internal Medicine, 6th Edition

792 PART VI Endocrine Disorders

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VetBooks.ir 15 15

13 13
FIG 48.17
Mean and range of random total serum T 4 (A) 11 11
and total serum T 3 (B) concentrations in
hyperthyroid cats. Seventy-five percent of
hyperthyroid cats have values within the box, 9 9
and the balance is within the limitation bars Serum T 4 (µg/dL) Serum T 3 (ng/mL)
above and below the box. Note that virtually all 7 7
hyperthyroid cats have abnormal or borderline
serum T 4 concentrations, whereas serum T 3
concentrations are less sensitive. The pink 5 5
region represents the normal reference range. 4 4
3 3
2 2
1 1
0 0
A Total serum T 4 B Total serum T 3

300 23 200 15.5

260 20 14
175
160 12 12
150
140
10 125 10
Serum T 4 (nmol/L) 100 8 Serum T 4 (µg/dL) Serum free T 4 (pmol/L) 100 8 Serum free T 4 (ng/dL)
120

80

60 6 75 6
4 50 4
40

2 25 2
20

0 0 0 0
A Normal Hyperthyroid Other illness B Normal Hyperthyroid Other illness

FIG 48.18
Box plots of serum total T 4 (A) and free T 4 (B) concentrations in 172 clinically normal
cats, 917 cats with untreated hyperthyroidism, and 221 cats with nonthyroidal disease.
See Fig. 48.9 for explanation. (From Peterson ME et al: Measurement of serum
concentrations of free thyroxine, total thyroxine, and total triiodothyronine in cats with
hyperthyroidism and cats with nonthyroidal disease, J Am Vet Med Assoc 218:529,
2001.)