49497-1

LOINC code 49497-1 identifies "Platelets [#/volume] in Blood by Estimate". In the Hematology world estimated cell counts have existed for many moons and they are reported either qualitatively or quantitatively and done strictly by blood smear review. Smear Estimated WBC and Platelet counts that aren't just reported as reduced/adequate/many that are actually estimated as a numeric result like an estimate of 4 K/cumm for WBC or 400 K/cumm for platelets. Like doing a retic count by counting so many fields on the smear type of estimate. This Platelet estimate count is a manual quantitative count. We report a number. See laboratory procedure: B. Platelet Count Smear Estimate: 1, Use the 100X oil immersion objective. 2. Estimate the average number of platelets per field using 10 different fields, where the RBCs are evenly dispersed. Avoid field in which RBCs strongly overlap as this will falsely increase the platelet estimate. Multiply this result by 20,000 to obtain an approximation of the platelet count. 3. A normal platelet count would show 8-20 plt/field; or one platelet per 10-30 RBCs. 4. NOTE: If platelet clumps or satellitism are seen, an estimate cannot be performed. Notify physician of problem. If indicated advise redraw in the appropriate anticoagulant, sodium citrate (blue-top). Order will need to be placed for a CBC SODIUM CITRATE test. This will automatically order both lav & blue tubes. III. REFERENCES: A. A Color Atlas and Instruction Manual of Peripheral Blood Cells Morphology, by Barbara H. O'Connor, 1984, p. 20. B. Principles and Procedures, Barbara A. Brown, 6th Edition, 1993, p. 104.

This code measures Platelets in Bld. It belongs to the HEM/BC class in the LOINC classification.

LOINC (Logical Observation Identifiers Names and Codes) is a universal standard for identifying laboratory and clinical observations. It is maintained by the Regenstrief Institute and used worldwide for health data exchange.