A Vortex Method to Disaggregate Platelets for Correct Counting in Pseudothrombocytopenia.

Pseudothrombocytopenia (PTCP) refers to the aggregation of platelets in anticoagulant blood in vitro and causes a false lower platelet count (PLT). For the purpose to achieve an accurate PLT, we presented an alternative vortex method to disaggregate platelet clumps and consequently generate a reliable PLT without a second venous puncture for patients. PLT, mean-platelet-volume (MPV), red blood cells (RBCs), hematoglobin (Hb), hematocrit (Hct) and white blood cells (WBCs) were evaluated before and after vortex in 221 specimens with PTCP using vortex method, and the PLT was also compared with 85 specimens disaggregated by citrate method. Twenty control samples were used to investigate mixing effect on complete blood counts in normal samples. One thrombocytopenia specimen was used to evaluate reproducibility of vortex. The mean PLT, MPV, RBCs, Hb, Hct and WBCs of 20 control specimens pre-vortex were 260.7 ± 53.4 × 10/L, 11.65 ± 0.85, 4.87 ± 0.46 × 10/L, 147.6 ± 13.8 g/L, 45.31 ± 4.04, 6.46 ± 1.41 × 10/L, and results of post-vortex were 252.9 ± 50.2 × 10/L, 11.66 ± 0.92, 4.95 ± 0.48 × 10/L, 149.1 ± 13.8 g/L, 45.19 ± 4.03, 6.35 ± 1.36 × 10/L respectively. Specimens with platelet clumps using vortex mixer had higher PLT after mixing, the mean pre-vortex PLT was 54.3 ± 35.2 × 10/L, and after vortexing PLT increased to 157.5 ± 58.8 × 10/L ( < ). MPV, RBCs, Hb, Hct and WBCs in 221 specimens were comparable before and after vortex mixing (all  > ). Vortex method might disaggregate platelet clumps sufficiently in most PTCP specimens, and obtain a relatively reliable PLT without the need of a second venous puncture.