title: Menstrual blood loss measurement: validation of the alkaline hematin technique for feminine hygiene products containing superabsorbent polymers.
abstract: OBJECTIVE
  To validate the alkaline hematin technique for measurement of menstrual blood loss using ultra-thin sanitary towels that contain superabsorbent polymer granules as the absorptive agent.
  
  
  METHODS
  Laboratory study using simulated menstrual fluid (SMF) and Always Ultra Normal, Long, and Night "with wings" sanitary towels.
  
  
  METHODS
  Keele Menstrual Disorders Laboratory.
  
  
  METHODS
  None.
  
  
  METHODS
  None.
  
  
  METHODS
  Recovery of blood, linearity, and interassay variation over a range of SMF volumes applied to towels. Because of the variable percentage of blood in menstrual fluid, blood recovery was assessed from SMF constituted as 10%, 25%, 50%, and 100% blood. The lower limit of reliable detection and the effect of storing soiled towels for up to 4 weeks at 15°C-20°C, 4°C, and -20°C before analysis were determined.
  
  
  RESULTS
  Ninety percent recovery was reproducibly achieved up to 30 mL applied volume at all tested SMF compositions, except at low volume or high dilution equivalent to <2 mL whole blood. Samples could be stored for 3 weeks at all tested temperatures without loss of recovery. The technique was suitable for processing towels individually or in batches.
  
  
  CONCLUSIONS
  The alkaline hematin technique is a suitable and validated method for measuring menstrual blood loss from Always Ultra sanitary towels that contain superabsorbent polymers.
authors.affiliation: Institute for Science and Technology in Medicine, Guy Hilton Research Centre, Hartshill, Stoke on Trent, United Kingdom. j.l.magnay@bemp.keele.ac.uk
authors.forename: Julia L
authors.initials: JL
authors.lastname: Magnay
authors.forename: Tracy M
authors.initials: TM
authors.lastname: Nevatte
authors.forename: Vandana
authors.initials: V
authors.lastname: Dhingra
authors.forename: Shaughn
authors.initials: S
authors.lastname: O'Brien
mesh_terms: D041342:Absorbent Pads / Q000592:standards; D000327:Adsorption; D001769:Blood / Q000378:metabolism; D001790:Blood Physiological Phenomena / Q000187:drug effects; D002138:Calibration; D004355:Drug Stability; D005260:Female; D006427:Hemin / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D052576:Menstrual Hygiene Products / Q000592:standards; D008598:Menstruation / Q000097:blood / Q000502:physiology*; D011108:Polymers / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D013997:Time Factors; D014592:Uterine Hemorrhage / Q000473:pathology
chemical_list: D011108:Polymers; D006427:Hemin