INTERNAL QUALITY CONTROL FOR ERYTHROCYTE SEDIMENTATION RATE USING PATIENT BLOOD SAMPLE

The erythrocyte sedimentation rate (ESR) test continues to be used as an important tool in many laboratories; either manually or as automated method. When automation is applied in clinical laboratories, it is imperative that reliable methods for calibration and appropriate control materials are available for monitoring the accuracy and precision of the results generated. But when the commercial control degenerates or is unavailable, alternative sources such as patient blood can be an alternative. Aims: a.To assess the usefulness of ESR values of patients’ sample in maintaining internal quality control. b. To use the patient blood sample in order to ascertain the precision of the ESR test results on two machines: Diesse Ves- MATIC 80™ (machine A and B).Materials and Methods: A retrospective cross-sectional study involving 219 blood samples over a period of 8 months was conducted at Kasturba Hospital, Manipal. The patient samples with normal ( 60 mm/hr) ESR (Group 2) were run on the 2 Diesse Ves- MATIC 80™ machines (A &B) against two level commercial controls on a daily basis. Statistics: Bland and Altman statistical analysis was applied for evaluating comparability of the methodologies. Results: Both groups showed a good concordance for all the ESR values and they were within 2SD. The results of higher ESR values were much better than the lower ESR values. Conclusions: The fresh patient blood samples as an internal quality control material showed good precision.