title: The relationship between the haemoglobin concentration and the haematocrit in Plasmodium falciparum malaria.
abstract: BACKGROUND
  Malaria is a very important cause of anaemia in tropical countries. Anaemia is assessed either by measurement of the haematocrit or the haemoglobin concentration. For comparisons across studies, it is often necessary to derive one measure from the other.
  
  
  METHODS
  Data on patients with slide-confirmed uncomplicated falciparum malaria were pooled from 85 antimalarial drug trials conducted in 25 different countries, to assess the haemoglobin/haematocrit relationship at different time points in malaria. Using a linear random effects model, a conversion equation for haematocrit was derived based on 3,254 measurements from various time points (ranging from day 0 to day 63) from 1,810 patients with simultaneous measurements of both parameters. Haemoglobin was also estimated from haematocrit with the commonly used threefold conversion.
  
  
  RESULTS
  A good fit was obtained using Haematocrit = 5.62 + 2.60 * Haemoglobin. On average, haematocrit/3 levels were slightly higher than haemoglobin measurements with a mean difference (+/- SD) of -0.69 (+/- 1.3) for children under the age of 5 (n = 1,440 measurements from 449 patients).
  
  
  CONCLUSIONS
  Based on this large data set, an accurate and robust conversion factor both in acute malaria and in convalescence was obtained. The commonly used threefold conversion is also valid.
authors.affiliation: Mahidol-Oxford Tropical Medicine Research Unit (MORU), Mahidol University, Faculty of Tropical Medicine, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Rd, Ratchathewi District, Bangkok 10400, Thailand. sue@tropmedres.ac
authors.forename: Sue J
authors.initials: SJ
authors.lastname: Lee
authors.forename: Kasia
authors.initials: K
authors.lastname: Stepniewska
authors.forename: Nicholas
authors.initials: N
authors.lastname: Anstey
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Ashley
authors.forename: Karen
authors.initials: K
authors.lastname: Barnes
authors.forename: Tran Quang
authors.initials: TQ
authors.lastname: Binh
authors.forename: Umberto
authors.initials: U
authors.lastname: D'Alessandro
authors.forename: Nicholas P J
authors.initials: NP
authors.lastname: Day
authors.forename: Peter J
authors.initials: PJ
authors.lastname: de Vries
authors.forename: Grant
authors.initials: G
authors.lastname: Dorsey
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Guthmann
authors.forename: Mayfong
authors.initials: M
authors.lastname: Mayxay
authors.forename: Paul
authors.initials: P
authors.lastname: Newton
authors.forename: Francois
authors.initials: F
authors.lastname: Nosten
authors.forename: Piero
authors.initials: P
authors.lastname: Olliaro
authors.forename: Lyda
authors.initials: L
authors.lastname: Osario
authors.forename: Loretxu
authors.initials: L
authors.lastname: Pinoges
authors.forename: Ric
authors.initials: R
authors.lastname: Price
authors.forename: Mark
authors.initials: M
authors.lastname: Rowland
authors.forename: Frank
authors.initials: F
authors.lastname: Smithuis
authors.forename: Robert
authors.initials: R
authors.lastname: Taylor
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: White
mesh_terms: D000465:Algorithms; D002675:Child, Preschool; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D016778:Malaria, Falciparum / Q000097:blood* / Q000175:diagnosis; D011237:Predictive Value of Tests
chemical_list: D006454:Hemoglobins