LETTER
Decreasing Liver Biopsy Complications
Michael J. Kovacs;
Michael Keeney; and
Ian Chin-Yee
1 September 1993 | Volume 119 Issue 5 | Pages 436-437
TO THE EDITOR:
Janes and Lindor's [1] criteria for outpatient liver biopsy include a prothrombin time less than 14 seconds. Garcia-Tsao and Boyer [2] cite a prothrombin time prolonged less than 3 seconds and a bleeding time of 
10 minutes. No mention was made of the bleeding history, probably the best predictor of postoperative bleeding [3]. Reliance by clinicians on the prothrombin time or bleeding time to predict postbiopsy bleeding is hampered by the difficulty in their use, interpretation, and generalizability.
Neither article specified the sensitivity of the reagents (International Sensitivity Index [ISI]), making it impossible to generalize a prothrombin time elevation to other institutions. If these criteria are for nonsensitive reagents (high ISI), then centers using sensitive reagents (low ISI) would need to allow for prolongation of the prothrombin time. Indication of the control range does not help because the normal range changes minimally with change in the ISI.
The use of the International Normalized Ratio (INR), which takes into account the patient's prothrombin time and the ISI of the reagent used, would allow more accurate comparisons of prothrombin times among different institutions [4]. The risk for bleeding in patients on oral anticoagulants has been clearly related to the level of the INR [4], but the ability of the INR (or prothrombin time) to predict surgical bleeding has not been prospectively examined.
The traditional use of the bleeding time to assess platelet function and to predict bleeding complications has been questioned [3, 5]. A normal bleeding time in a patient who has been taking aspirin may actually lead to a false sense of security regarding potential bleeding complications of liver biopsy.
We recommend that the INR be used in place of the prothrombin time or that the ISI of the reagents be specified if "reference criteria" are quoted, so that values can be compared. We also recommend that clinicians re-evaluate their use of both the bleeding time and prothrombin time as predictors of the bleeding complications of surgery.
1. Janes CH, Lindor KD. Outcome of patients hospitalized for complications after outpatient liver biopsy. Ann Intern Med. 1993; 118:96-8.
2. Garcia-Tsao G, Boyer JL. Outpatient liver biopsy: how safe is it? Ann Intern Med. 1993; 118:150-3.
3. Lind SE. The bleeding time does not predict surgical bleeding. Blood. 1991; 77:2547-52.
4. Hirsh J. Oral anticoagulant drugs. N Engl J Med. 1991; 324:1865-75.
5. Rodgers RP, Levin J. A critical reappraisal of the bleeding time. Semin Thromb Hemost. 1990; 16:1-20.
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