Utility of automated counting to determine absolute neutrophil counts and absolute phagocyte counts for pediatric cancer treatment protocols.
BACKGROUND
Absolute neutrophil counts (ANCs) and absolute phagocyte counts (APCs) are used to guide cancer treatment. Although automated counting could replace manual counting, data showing correlations are lacking. By analyzing blood samples from children undergoing cancer treatment, the authors determined whether ANCs and APCs obtained by automated methods correlated positively with ANCs and APCs obtained manually.


METHODS
The authors analyzed 3640 consecutive peripheral blood samples. Leukocyte counts determined by Beckman-Coulter Gen-S or HmX analyzers (Beckman-Coulter, Miami, FL) were used to calculate counts obtained by automated or manual methods. Automated differential counts were obtained by automated analyzers and manual differential counts were performed by medical technologists. Counts underwent linear regression analysis. The authors evaluated 5 cutoff values for ANCs and APCs commonly used in decision-making related to cancer treatment: 300/muL, 500/muL, 750/muL, 1000/muL, and 1500/muL. Manually determined ANCs and APCs served as standards to determine the sensitivity, specificity, positive and negative predictive values, and kappa coefficient for automated counting.


RESULTS
R(2) values were 0.81 for ANCs determined by manual and automated methods and 0.84 for APCs determined by both methods. The specificity of the automated method was > 90% for all ranges of ANCs and APCs, except one (APCs < 300/muL). There was excellent agreement (kappa > 0.9) between ANCs determined by manual and automated methods and APCs calculated by both methods.


CONCLUSIONS
Automated methods of determining ANCs and APCs for children undergoing cancer treatment were reliable and can replace manual counting. Blood smear examination to validate ANCs and APCs determined by automated methods was needed only in selected cases.
Hijiya
Nobuko
N
Department of Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA. nobuko.hijiya@stjude.org
Onciu
Mihaela
M
Howard
Scott C
SC
Zhang
Zhe
Z
Cheng
Cheng
C
Sandlund
John T
JT
Kyzer
Emily P
EP
Behm
Fred G
FG
Pui
Ching-Hon
CH
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001331:Automation; D001772:Blood Cell Count; D002648:Child; D005189:False Positive Reactions; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy; D009504:Neutrophils; D010347:Patient Care Planning; D010586:Phagocytes; D011237:Predictive Value of Tests; D015203:Reproducibility of Results