title: Hemoglobin assay in anemic patients with a photothermal spectral-domain optical coherence reflectometric sensor.
abstract: BACKGROUND
  We recently introduced an optical sensor, termed photothermal spectral-domain optical coherence reflectometer (PT SD-OCR), capable of direct measurement of hemoglobin concentration ([Hb]) without chemicals and pre-processing of blood. PT SD-OCR measures [Hb] by quantifying refractive index changes of blood samples due to photothermal effect under the irradiation of 532-nm light. We evaluated diagnostic accuracy and precision of PT SD-OCR in anemic patients.
  
  
  METHODS
  We used PT SD-OCR to measure [Hb] in 50 anemic patients, and examined its accuracy against a hematology analyzer (ADVIA 2120i, Siemens AG). Its precision was assessed by examining the SD and CV based on 20 repeated measurements on 3 blood samples. Its performance was also compared with a hemoglobinometer (HemoCue 201+, HemoCue).
  
  
  RESULTS
  The PT SD-OCR demonstrated good correspondence with the hematology analyzer with a Pearson's correlation coefficient of 0.992 and a bias of -0.055 g/dl. Standard deviation and CV were measured to be <0.25 g/dl and <2.05%.
  
  
  CONCLUSIONS
  Simple and chemical-free operation of PT SD-OCR enabled rapid and accurate measurement of [Hb] in anemic patients. The sensor is expected to facilitate clinical procedures related to blood-related disorders in patient care.
authors.affiliation: School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Hun
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine, Konyang University College of Medicine, Daejeon 302-718, Republic of Korea.
authors.forename: Sungwook
authors.initials: S
authors.lastname: Song
authors.affiliation: School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Jinyeong
authors.initials: J
authors.lastname: Yim
authors.affiliation: Department of Laboratory Medicine, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Hyun Ok
authors.initials: HO
authors.lastname: Kim
authors.affiliation: School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea. Electronic address: cjoo@yonsei.ac.kr.
authors.forename: Chulmin
authors.initials: C
authors.lastname: Joo
mesh_terms: D000740:Anemia / Q000097:blood*; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D013817:Thermography; D041623:Tomography, Optical Coherence
chemical_list: D006454:Hemoglobins
keywords: Anemia; Hemoglobin concentration; Optical interferometer; Optical sensor; Photothermal effect