Synovial and Ascitic Fluid Evaluation With the Advia Analyzer
Synovial and Ascitic Fluid Evaluation With the Advia Analyzer
Sixty samples had results from Advia's regular and TNC channels, and from manual counting. Because the values were nearly identical, with a high correlation coefficient for the 2 Advia channels (r = .998), we subsequently compared the hemocytometer counts and fluid smear reviews only with the regular channel results that also reported the proportion of neutrophils. The Advia regular channel results were nearly identical to those obtained with manual counting Table 1 for both synovial and ascitic fluids. The proportion of neutrophils on the Advia was harmonized and highly correlated with counts on the fluid smear review. Results using the Spearman rank correlation were high, similar to Pearson correlation coefficients, and the relationships were linear.
Eight values were concordantly high and 32 concordantly low for ascitic fluid, with only 2 misclassifications: 250 cells/μL compared with 240 cells/μL, and 220 cells/μL compared with 290 cells/μL for manual and Advia analyzer counts, respectively. Results were also concordant for neutrophil differential counts (fluid smear review compared with the Advia analyzer for 5 samples: 49% vs 44%, 6% vs 9%, 11% vs 17%, 25% vs 26%, and 4% vs 11%, respectively).
For synovial fluid, the values counted on the hemocytometer were lower if no enzyme was added in 18 of 18 cases (P < .001). The median values increased from 68 cells/μL to 515 cells/μL after the addition of hyaluronidase. Nevertheless, at an upper limit of the reference interval of 1,999 cells, 11 of 11 had low-low values and 6 of 6 had high-high values. In 1 discordant case, 432 cells/μL increased to 4,800 cells/μL after the addition of hyaluronidase. This case demonstrated the same discordance with the Advia analyzer. After adding hyaluronidase, no discordant values were found between the Advia and the hemocytometer. Results were also concordant for the proportion of neutrophils (Table 1). A cutoff value of less than 90% neutrophils has been used to rule out septic arthritis. We had only 3 cases with more than 90% on the fluid smear review (91%, 91%, and 92%), with 92%, 87%, and 91%, respectively, determined on the Advia analyzer.
Three samples had a high number of RBCs. To count the cells manually, the RBCs were hemolyzed. The manual counts were nearly identical to those found with the Advia. All the other samples had less than or equal to 20,000 cells/μL.
Results
Sixty samples had results from Advia's regular and TNC channels, and from manual counting. Because the values were nearly identical, with a high correlation coefficient for the 2 Advia channels (r = .998), we subsequently compared the hemocytometer counts and fluid smear reviews only with the regular channel results that also reported the proportion of neutrophils. The Advia regular channel results were nearly identical to those obtained with manual counting Table 1 for both synovial and ascitic fluids. The proportion of neutrophils on the Advia was harmonized and highly correlated with counts on the fluid smear review. Results using the Spearman rank correlation were high, similar to Pearson correlation coefficients, and the relationships were linear.
Eight values were concordantly high and 32 concordantly low for ascitic fluid, with only 2 misclassifications: 250 cells/μL compared with 240 cells/μL, and 220 cells/μL compared with 290 cells/μL for manual and Advia analyzer counts, respectively. Results were also concordant for neutrophil differential counts (fluid smear review compared with the Advia analyzer for 5 samples: 49% vs 44%, 6% vs 9%, 11% vs 17%, 25% vs 26%, and 4% vs 11%, respectively).
For synovial fluid, the values counted on the hemocytometer were lower if no enzyme was added in 18 of 18 cases (P < .001). The median values increased from 68 cells/μL to 515 cells/μL after the addition of hyaluronidase. Nevertheless, at an upper limit of the reference interval of 1,999 cells, 11 of 11 had low-low values and 6 of 6 had high-high values. In 1 discordant case, 432 cells/μL increased to 4,800 cells/μL after the addition of hyaluronidase. This case demonstrated the same discordance with the Advia analyzer. After adding hyaluronidase, no discordant values were found between the Advia and the hemocytometer. Results were also concordant for the proportion of neutrophils (Table 1). A cutoff value of less than 90% neutrophils has been used to rule out septic arthritis. We had only 3 cases with more than 90% on the fluid smear review (91%, 91%, and 92%), with 92%, 87%, and 91%, respectively, determined on the Advia analyzer.
Three samples had a high number of RBCs. To count the cells manually, the RBCs were hemolyzed. The manual counts were nearly identical to those found with the Advia. All the other samples had less than or equal to 20,000 cells/μL.
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