title: Corrected to uncorrected? The metabolic conundrum of hypertrophic pyloric stenosis.
abstract: OBJECTIVE
  The purpose of this study was to evaluate factors associated with repeat blood testing after establishment of normal metabolic parameters and factors associated with reversal of metabolic correction back an uncorrected form in preoperative management of infants with Hypertrophic Pyloric Stenosis (HSP).
  
  
  METHODS
  A retrospective review of infants with HSP undergoing repeat serum chemistries after already having normal labs were identified. Variables associated with repeating normal bloodwork and reversion of normal to abnormal labs were identified. Associations between reversion to abnormal and ordering of repeat labs were determined.
  
  
  RESULTS
  255 cases were studied with a median of 2 lab tests drawn per patient (range 1-9). Of 142 serum chemistry tests repeated after a normal test, 27% became abnormal, most commonly hyperkalemia. 61% of these went to surgery. No variables were associated with a normal test becoming abnormal. However, a time lapse of >12h was associated with the reordering of bloodwork despite it already being normal.
  
  
  CONCLUSIONS
  There is little evidence to support need for repeat serum chemistry testing in cases of HPS once normality has been established. Development of clinical pathways to reduce the use of unnecessary serum testing may improve efficiency of patient care and limit unnecessary resource utilization.
  
  
  METHODS
  Retrospective Case control: 3b.
authors.affiliation: Division of Pediatric General Surgery, IWK Health Centre; Dalhousie University; Halifax, Nova Scotia, Canada. Electronic address: natalie.yanchar@albertahealthservices.ca.
authors.forename: Natalie L
authors.initials: NL
authors.lastname: Yanchar
authors.affiliation: Division of Pediatric General Surgery, IWK Health Centre; Dalhousie University; Halifax, Nova Scotia, Canada.
authors.forename: Sowmith
authors.initials: S
authors.lastname: Rangu
mesh_terms: D015415:Biomarkers / Q000097:blood; D000066491:Clinical Decision-Making; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D006947:Hyperkalemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010818:Practice Patterns, Physicians'; D011300:Preoperative Care / Q000379:methods*; D046248:Pyloric Stenosis, Hypertrophic / Q000097:blood / Q000150:complications / Q000601:surgery / Q000628:therapy*; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D015415:Biomarkers
keywords: Biochemical profile; Hyperkalemia; Metabolic alkalosis; Pyloric stenosis; Resource utilization