BSP retention test

The results of the BSP retention test are expressed in terms of the percentage of BSP remaining in the circulation at a given time after the injection. Most investigators have taken a single sample at a given time in the period from 30 to 60 minutes after the injection, with 45 minutes the most popular choice. Robinson (R14), however, took blood samples... 

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... 

The BSP retention test has been used in studies on the factors in recovery from infective hepatitis. Thus the normal ability to handle BSP returns more quickly with cortisone therapy (H24). Ability to remove BSP improves more rapidly on a high protein diet (C13). In infective hepatitis, a small percentage of patients relapse, with return of persistently abnormal biochemical values, but BSP retention values obtained early in convalescence are not helpful in predicting which of the patients will relapse (C13). 

BOO. Burnett, W., BSP retention test in acute cholecystitis and in some other acute intra-abdominal conditions. Lancet II, 488-490 (1954). 

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). 

Retention of dyes, such as BSP, is increased in acute and chronic hepatitis and in intra- and extrahepatic biliary obstruction. Gross retention (>60%) occurs more commonly in patients with hepatocellular jaundice than with obstructive jaundice (R5, S42), but there is considerable overlap between the two groups and retention tests are consequently of little value in distinguishing between hepatocellular and obstructive jaundice or in assessing hepatocellular function in the presence of biliary obstruction. Measurements of the fractional disappearance rate (a), the hepatic storage capacity (S), or the maximal biliary excretion (Tm) have likewise not proved helpful in discriminating between the two conditions (S17). 

Attempts have been made to allow for the effect of biliary obstruction by the use of a correction factor based on the 1-minute serum bilirubin concentration as a measure of the degree of obstruction (Z3). However BSP retention values corrected in this way were foimd to be less valuable in the differential diagnosis of jaundice than the results of the cephalin flocculation test or the thymol turbidity test (M21). 

Obesity is associated with increased BSP retention when the standard test is used 20 patients who were grossly (50-91%) overweight all had increased BSP retention, viz. 15 (6-33)% (Z2). Although biochemical and biopsy evidence of liver dysfunction was found in 50% of the group, it is likely that the dose of BSP (5 mg/kg) was an important contributing factor because it was almost certainly higher relative to liver mass than in normal persons (see Section 5.1). 

An alternative procedure, which has been used (S28) to allow for background absorbance, consists of analyzing a sample taken before administration of BSP as a blank, but this will not allow for a variable amount of hemolysis in collecting blood specimens. It may, however, be necessary to analyze a preinjection sample if a dye test is being carried out a short time after a previous dye test to allow for any BSP remaining in the plasma. This is particularly important in the study of patients with marked BSP retention for, in such patients, measurable amounts of dye may remain in the plasma for days (G5, Jl). 

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. 

Statistical Methods. Means of treatment groups for plasma retention of BSP, plasma osmolality, total plasma protein concentration and urine flow rates were compared by students t test for independent sample means (17). Plasma enzyme activity data were converted to a quantal form and analyzed by the Fischer Exact Probability Test (18). Values greater than 2 standard deviations (P < 0.05) from the control value were chosen to indicate a positive response in treated fish. 

Rifamycin increases the retention of bilirubin by inhibiting its excretion rate. This antibiotic has no effect on conjugation (A3). It is probable that rifamycin would increase plasma retention of BSP, but this has not been tested. 

The place of dye tests in the investigation of the jaundiced patient is another aspect on which further studies are required. Biliary obstruction itself causes dye to be retained in plasma so that in a jaundiced patient it is not known to what extent a high dye retention value is due to biliary obstruction or to hepatocellular impairment. It is possible, however, that mathematical analysis of plasma dye disappearance curves may allow the two components to be separately assessed. With BSP, measurement of dye conjugates in plasma offer another means of separating the effects of biliary obstruction from those of hepatocellular failure, although results to date have not been promising in the assessment of individual patients. 

A test that can be used to assess liver function when other liver function tests are normal. It is a test of the ability of the liver to conjugate and excrete the dye bromsulphthalein (BSP). It consists of an intravenous injection of the dye followed by the collection of blood specimens up to 45 minutes after the injection. Bromsulphthalein is then measured in the serum samples by adding alkali which renders the dye purple. In normal subjects less than 5% of the dose should remain in the circulation after 45 minutes. Increased retention of BSP is a sensitive index of hepatic dysfunction although false positives may occur if there is impaired circulation in the liver. 

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