The Urinary Metanephrine-to-Creatinine Ratio for the Diagnosis of
Pheochromocytoma
Clinical Question
How good is the urinary metanephrine-to-creatinine ratio in diagnosing a
pheochromocytoma?
Clinical Bottom Line
- This ratio has a positive Likelihood ratio of 43 and a negative likelihood
ratio of zero (0).
- However, despite a 5% increase in sensitivity over the comparable test (24
hr total metanephrines), there is no difference in the likelihood ratios of
either test, positive or negative.
The Evidence
|
|
Pheo
|
|
|
|
|
|
present
|
absent
|
+ LR
|
-LR
|
| Urinary MCR
|
positive
|
20
|
23
|
43
|
0
|
|
negative
|
0
|
970
|
|
|
|
totals
|
20
|
993
|
|
|
|
|
sensitivity
|
specificity
|
|
|
|
|
1.00
|
0.977
|
|
|
Comments
- Methods were described, but not in sufficient detail to permit replication,
although this is a minor flaw.
- Patients selected for entry into this study were patients sent to a
tertiary care center for further evaluation. Therefore, this patient population
is NOT truly representative of the population at large, for which the overall
prevalence is < 0.1%.
- The results of this study are significant, nonetheless, but must be taken
with a grain of salt. Previous studies (and this study) have demonstrated very
similar results for the 24 hr urine test for metanephrines. The absolute
increase in sensitivity is only 5%.
APPRAISED BY: Robert Bruha, MD
DATE: September 8, 1996
Heron E, et al. The Urinary Metanephrine-to-Creatinine Ratio for the
Diagnosis of Pheochromocytoma. Ann Int Med 1996;145:300-303.
