SURGICAL PATIENTS WITH SURPRISING LABORATORY DATA

Preoperative laboratory tests were performed on elective ambulant orth opaedic patients (n=26) on the afternoon after their arrival in hospit al and on the next morning before the operation. Significantly lower c oncentrations of leukocytes, albumin, total protein, platelets, and to tal calcium were observed in samples taken in the morning. Posture and chronobiological rhythms may be responsible for these changes. An ove rnight change in laboratory values may lead to unnecessary further inv estigations and postponement of surgery. The clinician should be aware of the effects of preanalytical factors on laboratory data.