Table 1.

Examples of free text associated with read terms analysed by the freetext matching algorithm

Analysis mode	Read term	Free text	Structured output
Standard	55...11 Angiography - CVS	coronary severe triple vessel disease + impaired function	Read G340.11 Triple vessel disease of the heart
Standard	G20..00 Essential hypertension	176/100 but only taking doxaz 4mg od not bd as pw intended - increase to 4mg bd, pn recheck 4w please. otherwise isq but recent diagnosis ca prostate - seeing urol 1w - reassured re treatablility of this nowadays	Systolic BP: 176, Diastolic BP: 100, Follow up: 4 weeks, Read B46..00 Malignant neoplasm of prostate
Standard	32...00 Electrocardiography	sinus bradycardia (58 bpm) nonspecific intraventricular conduction delay	Read R059.00 [D]Sinus bradycardia, Pulse: 58
Standard	55...12 Angiogram	ct did not show renal artery stenosis.	Negative: Read P769000 Renal artery stenosis
Standard, append	G581.00 Left ventricular failure	acute give lasix and o2 and admitted	Read G581000 Acute left ventricular failure, Read 8H3Z.00 Other hospital admission NOS
Standard, append	14A4.00 H/O: myocardial infarct >60	had an mi in 1996	Past medical history: Read G30..00 Acute myocardial infarction, date: year 1996
Death	22J..12 Death	found dead by family this afternoon, called ambulance, cd 1415hrs, sudden death, rpt to coroner	Read 213100 [D]Found Dead, Time: 14:15, OXMIS T4002 SUDDEN DEATH
Labtest	42J..00 Neutrophil count	original result: ’neutrophil count’ = 4.17 x109 / l (1. 5 - 7. 5)	Lab result: 4.17
Sicknote	9D2..00 MED5 - doctor’s special stat.	### 09/01/2007 1 month heart problems, ###	Sickness certificate date: 9-Jan-2007, duration: 1 month
Examples of errors in interpretation of free text
Standard	5853.11 Echocardiogram	significant mitral regurg	(no output; ‘regurg’ not recognised as an abbreviation for ‘regurgitation’)
Standard	33B9500 Exercise tolerance test abnormal	pt exercised according to the bruce protocol for 4 mins 39secs. he developed chest discomfort during the test with very significant, >3mm, st depression in leads v4, 5 and 6 and leads 2, 3 avf. ###	Read R065600 [D]Chest discomfort, Read E2B..00 Depressive disorder NEC (incorrect interpretation of ECG finding of ST segment depression)