Indocyanine green retention test

An indocyanine green retention test similar to the BSP retention test (C16) gave a mean retention value in health of 3.9%, 20 minutes after a... 

There are conflicting reports, however, of the relative sensitivities of different tests in the recovery phase. One group of patients tended to retain abnormal flocculation reactions and elevated 1-minute serum bilirubin values longer than abnormal BSP values (N5). Other investigators have found decreased BSP removal rates in patients who had had infective hepatitis but who no longer showed other clinical or biochemical evidence of the disease (II, D7, W32). Abnormal BSP retention persists for longer than abnormal indocyanine green disposal (L5). 

The majority of investigations in patients have involved measurement of dye retention only. The retention test, at least with BSP, fails to take into account the shape of the plasma decay curve. Thus, in some patients the plasma dye concentration falls more slowly than normal during the initial phase but still reaches a normal level at 45 minutes. The plasma disappearance curve of indocyanine green more closely approximates a single-phase exponential curve during the period of the test, and if it was considered desirable to collect only one sample it would be preferable to use indocyanine green. The optimal dose of dye to be administered in a retention test cannot be defined until further comparative studies have been done. It would be sensible meanwhile to use the standard dose (5 mg/kg) if only to obtain results comparable with the majority of those obtained during the past 20 years. 

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