Being an outstanding physician and lifelong learner requires stoking the flames of clinical curiosity. In Chiefs’ Inquiry Corner (CIC) we attempt to succinctly answer actual clinical questions that have been raised on the wards and in the clinics of NYU’s teaching hospitals. Our answers are not meant to be all encompassing or practice changing but rather to serve as springboards for further exploration. For those of us with short attention spans, we hope CIC satisfies that craving for a morsel of knowledge in a digestible format.
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Free testosterone is generally not needed in the workup of male hypogonadism, as total testosterone is generally a good proxy, and a more reliable test (with some caveats- see below!). One exception to this rule is in patients with a suspected sex hormone binding globulin deficiency (as in the case of obesity, type 2 diabetes or steroid exposure), in whom total testosterone can be low while the free fraction remains normal. If measuring free testosterone, be aware that the most commonly used assay, the direct immunoassay (or analog assay), is notoriously unreliable. Instead, order free testosterone by equilibrium dialysis, a test which is only available in a few specialized endocrinology labs.
References: Free Testosterone
In men with signs and symptoms of possible hypogonadism, the Endocrine Society recommends testing for fasting, morning total testosterone (TT) levels on two separate occasions. There is considerable variability in TT measurements. In a study of 1133 laboratories using 14 different TT assays using samples from a single hypogonadal man, the measured values ranged from 45 to 365 ng/dL, showing wide variability and inaccuracy. TT assays used for the diagnosis of hypogonadism must be certified by the CDC Hormone Standardization Program in order to improve specificity, sensitivity, and precision.
Severe alcohol withdrawal syndrome (SAWS), defined as autonomic and psychological symptoms and withdrawal seizures, delirium tremens or both, has a mortality rate of up to 15% without early aggressive management. The Prediction of Alcohol Withdrawal Severity Scale (PAWSS), which tallies 10 risk factors and exam findings, has a 93% sensitivity and 99% for predicting SAWS if a patient has over 4 points. This corresponds to a positive likelihood ratio of 174!
References: Rational Clinical Exam- Alcohol Withdrawal