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Table 2 Frequencies of ICD-9 chapters & specific diagnostic codes from the physician claims among persons who had a laboratory test for pertussis by case status

From: How well do ICD-9 physician claim diagnostic codes identify confirmed pertussis cases in Alberta, Canada? A Canadian Immunization Research Network (CIRN) Study

ICD 9 CHAPTER ICD-9 CODES CASE STATUS
TP (%) FP (%) FN (%) TN (%)
I. Infectious and parasitic diseases 001–139 872 (100) 4563 (100) 0 656 (4.3)
  033 (whooping cough) 747 (86.0) 0 0 21 (0.1)
033.0 (B. pertussis) 0 3949 (87.0) 0 0
033.1 (B. parapertussis) 12 (1.4) 56 (1.3) 0 0
033.8 (Whooping cough, other specified organism) 2 (0.2) 34 (0.8) 0 0
033.9 (Whooping cough, other unspecified organism) 111 (12.7) 524 (11.4) 0 2 (>0.1)
Other codes (001–032.9; 034–139) 0 0 0 633 (4.2)
II. Neoplasms 140–239 0 0 0 110 (0.7)
III. Endocrine, nutritional and metabolic diseases and immunity disorders 240–279 0 0 0 299 (2.0)
IV. Diseases of blood and blood-forming organs 280–289 0 0 0 38 (0.2)
V. Mental disorders 290–319 0 0 0 614 (4.0)
VI. Diseases of the nervous system and sense organs 320–389 0 0 0 1226 (8.0)
VII. Diseases of the circulatory system 390–459 0 0 0 255 (1.7)
VIII. Diseases of the respiratory system 460–519 0 0 1388 (100) 3256 (21.4)
  460–466 (Acute respiratory infections) 0 0 1061 (76.4) 2550 (16.8)
470–479 (Other diseases of upper respiratory tract) 0 0 41 (3.0) 113 (0.7)
480–487 (Pneumonia and influenza) 0 0 118 (8.5) 139 (0.9)
490–496 (Chronic obstructive pulmonary disease and allied conditions) 0 0 159 (11.5) 412 (2.7)
500–508 (Pneumoconiosis and other lung diseases due to external agents) 0 0 0 3 (>0.1)
510–519 (Other disease of respiratory system) 0 0 9 (0.6) 39 (0.2)
IX. Diseases of the digestive system 520–579 0 0 0 374 (2.4)
X. Diseases of the genitourinary system 580–629 0 0 0 675 (4.4)
XI. Complications of pregnancy, childbirth and the puerperium 630–676 0 0 0 190 (1.2)
XII. Diseases of the skin and subcutaneous tissue 680–709 0 0 0 722 (4.7)
XIII. Diseases of the musculoskeletal system and connective tissue 710–739 0 0 0 1095 (7.2)
XIV. Congenital anomalies 740–759 0 0 0 221 (1.4)
XV. Certain conditions originating in the perinatal period 760–779 0 0 0 1951 (12.8)
XVI. Symptoms, signs and ill-defined conditions 780–799 0 0 0 2130 (14.0)
XVII. Injury and poisoning 800–999 0 0 0 1360 (9.0)
  Total 872 4563 1388 15172
  1. TP True Positive (physician diagnosed case that was also laboratory test positive for pertussis), FP False Positive (Physician diagnosed case that was laboratory test negative for pertussis), FN False Negative (Physician did not diagnose pertussis, but laboratory test positive for pertussis), TN True Negative (physician did not diagnose pertussis, laboratory test negative for pertussis)