Hematological health-related intervals estimated using an indirect method in order to satisfy the accreditation standards

 The estimation of reference limits represents quite a taxing task for laboratories which frequently adopt the limits suggested by manufacturers or those reported in the literature. This practice does not meet the requirements of accreditation programs (i.e. Essential Criteria, Clinical Pathology Accreditation) that require laboratories to produce or check all their reference intervals. We collected 15 244 hematological results from females aged 0–99 years obtained by the Rovereto Hospital Laboratory and calculated the reference intervals, or to be more precise the health-related intervals, using an indirect method (based on all the inpatient and outpatient results). All the measurements were carried out using an automatic Coulter STK S analyzer, and the results were transferred to Verona by e-mail. The results for hemoglobin were: <1 year (n=154)=90–171 g/l; 2–8 years (n=619)=104–136 g/l; 9–14 years (n=322)=118–143 g/l; 15–44 years (n=6329)=106–144 g/l; 45–75 years (n=4893)=107–148 g/l; 75–99 years (n=2927)=90–153 g/l. The results appear different from the results currently used by Rovereto Hospital (120–160 g/l) but comparable to those reported in the literature with the exception of the subjects under 1 year and over 75 years, probably due to the excess of "diseased" subjects in these classes. The indirect method allows even small laboratories to produce or check their reference intervals for all age groups, increasing the clinical effectiveness of laboratory results and satisfying the accreditation standards. Received: 15 April 2000 · Accepted: 20 April 2000