title: Faecal calprotectin levels differentiate intestinal from pulmonary tuberculosis: An observational study from Southern India.
abstract: BACKGROUND
  Current methods to establish the diagnosis of intestinal tuberculosis are inadequate.
  
  
  OBJECTIVE
  We aimed to determine the clinical features of intestinal tuberculosis and evaluate inflammatory biomarkers in intestinal as well as pulmonary tuberculosis.
  
  
  METHODS
  We recruited 38 intestinal tuberculosis patients, 119 pulmonary tuberculosis patients and 91 controls with functional gastrointestinal disorders between October 2009 and July 2012 for the investigation of clinical features, C-reactive protein (CRP), faecal and serum calprotectin. Faecal calprotectin ≥200 µg/g was used as a cut-off to determine intestinal inflammation of clinical significance. Three patient categories were established: (a) pulmonary tuberculosis and faecal calprotectin <200 µg/g (isolated pulmonary tuberculosis); (b) pulmonary tuberculosis and faecal calprotectin ≥200 µg/g (combined pulmonary and intestinal tuberculosis); (c) isolated intestinal tuberculosis.
  
  
  RESULTS
  Common clinical features of intestinal tuberculosis were abdominal pain, fatigue, weight loss and watery diarrhoea. Intestinal tuberculosis patients had elevated median CRP (10.7 mg/l), faecal calprotectin (320 µg/g) and serum calprotectin (5.7 µg/ml). Complete normalisation of CRP (1.0 mg/L), faecal calprotectin (16 µg/g) and serum calprotectin (1.4 µg/ml)) was seen upon clinical remission. Patients with combined pulmonary and intestinal tuberculosis had the highest levels of CRP (53.8 mg/l) and serum calprotectin (6.5 µg/ml) and presented with signs of more severe disease.
  
  
  CONCLUSIONS
  Calprotectin analysis reveals intestinal tuberculosis in patients with pulmonary tuberculosis and pinpoints those in need of rigorous follow-up.
authors.affiliation: Unger-Vetlesen Institute, Department of Medicine, Lovisenberg Diaconal Hospital, Oslo, Norway ; Faculty of Medicine, University of Oslo, Norway.
authors.forename: Geir
authors.initials: G
authors.lastname: Larsson
authors.affiliation: Population Health and Research Institute, Medical College, Trivandrum, Kerala, India.
authors.forename: Koticherry Thrivikrama
authors.initials: KT
authors.lastname: Shenoy
authors.affiliation: Thoothukudi Government Medical College, Tuticorin, Tamil Nadu, India.
authors.forename: Ramalingom
authors.initials: R
authors.lastname: Ramasubramanian
authors.affiliation: Government Rajaji Hospital, Madurai, Tamil Nadu, India.
authors.forename: Lakshmikanthan
authors.initials: L
authors.lastname: Thayumanavan
authors.affiliation: Population Health and Research Institute, Medical College, Trivandrum, Kerala, India.
authors.forename: Leena Kondarappassery
authors.initials: LK
authors.lastname: Balakumaran
authors.affiliation: Institute of Health and Society, Faculty of Medicine, University of Oslo, Norway.
authors.forename: Gunnar A
authors.initials: GA
authors.lastname: Bjune
authors.affiliation: Department of Gastroenterology and Hepatology, Institute of Clinical Medicine, Oslo University Hospital Ullevål, Oslo, Norway.
authors.forename: Bjørn A
authors.initials: BA
authors.lastname: Moum
keywords: CRP; Intestinal tuberculosis; biomarker; calprotectin; clinical features; diagnosis; follow-up; pulmonary tuberculosis; treatment response