Table 1.
Characteristics of the included studies
| Study and country | Study design | Setting | Targeted test users | Target tests | Thyroid tests |
|---|---|---|---|---|---|
| Adlan et al,22 UK | Before and after; single site | Medical assessment unit (acutely ill hospital patients) | Physicians | TFTs only | TSH, FT4, FT3, TPOAb, TRAb |
| Baker et al,23 UK | Cluster RCT | GP practices | GPs, locums, GPs in training and nurses | 5 frequently ordered laboratory tests suspected of being inappropriately ordered | TSH and FT4 |
| Berwick and Coltin,17 USA | Controlled cross-over; 3 sites | Ambulatory centres at health maintenance organisation | Internists and adult nurse practitioners | 13 laboratory and imaging tests suspected of being excessively ordered | TT4 |
| Chu et al,24 Australia | Before and after; single site | Adult tertiary referral teaching hospital ED | Interns and residents | Frequently ordered blood tests suspected of being excessively ordered | TFTs unspecified |
| Cipullo and Mostoufizadeh,19 USA | Before and after; single site | Community hospital | Medical staff (unspecified) | A range of high-volume laboratory procedures | TFTs unspecified but change in TT3 rate used as a measure of impact |
| Daucourt et al,25 France | Cluster RCT | General and psychiatric hospitals | Physicians | TFTs only | TSH, FT4, FT3, TRH test |
| Dowling et al,26 USA | Before and after; single site | Innercity community health centre | Family practice residents | TSHs only (complete blood count with differential used as a comparator) | TSH |
| Emerson and Emerson,27 USA | Before and after; single site | University medical centre | Residents | All laboratory tests | TSH, FT3, FT4, TT3, TT4 (individual and cascade) |
| Feldkamp and Carey,28 USA | Before and after; single site | Metropolitan hospital and 22 satellite clinics (inpatients and outpatients) | Physicians | TFTs only | TSH, TT3, TT4 |
| Gama et al,18 UK | Controlled study; single site | District general hospital (inpatients and outpatients) | General medicine physicians | All laboratory tests | TFTs unspecified |
| Grivell et al,29 Australia | Before and after; single site | Tertiary care community hospital | Consultants | 55 most commonly requested laboratory tests or test groups | TT4 |
| Hardwick et al,44 Canada | Before and after; multiple sites | All non-hospital-based laboratories in British Columbia | All users of non-hospital-based laboratories | TFTs only | TT3, TT4 |
| Horn et al,45 USA | Interrupted time series with a parallel control group; multiple sites | Alliance of 5 multispecialty group practices | Primary care physicians | 27 laboratory tests | TSH |
| Larsson et al,30 Mindemark and Larsson31 (follow-up), Sweden | Before and after; multiple sites | Primary healthcare centres | GPs and laboratory technicians | Various laboratory tests | TSH, FT4, TT4, TT3 |
| Nightingale et al,32 UK | Before and after; single site | Supraregional liver unit at teaching hospital | House officers | Various laboratory tests | TSH |
| Rhyne and Gehlbach,43 USA | Before and after; single site | Family medicine centre | Physicians | TFTs only | Thyroid function panel including TT4 and TT3 |
| Schectman et al,33 USA | Controlled study; single site | Primary care health maintenance organisation | Physicians, physician assistants and nurse practitioners | TFTs only | TSH, TT4, TT3 |
| Stuart et al,34 Australia | Before and after; single site | Urban public hospital ED | Consultants, registrars, junior medical officers and casual medical staff | All laboratory tests | TFTs unspecified |
| Thomas et al,10 UK | Cluster RCT | Primary care practices in 1 NHS covered area | Family practitioners | 9 laboratory tests suspected of being inappropriately ordered | TSH |
| Tierney et al,35 USA | RCT; single site | Academic general medicine practice | Physicians (residents and faculty) | 8 commonly ordered diagnostic tests | TSH |
| Tomlinet al,36 New Zealand | Controlled study; multiple sites | New Zealand primary care | All GPs on the New Zealand Medical Council's register compared with locum GPs and other medical specialists | TFTs only (but related programmes targeted inflammatory response tests and tests for infectious diarrhoea) | TSH, FT3, FT4 |
| Toubert et al,37 France | Before and after; single site | Teaching hospital | Physicians (various specialties, including endocrinologists) | TFTs only | TSH, FT3, FT4, TPOAb, TRAb, TgAb |
| van Gend et al,38 The Netherlands | Before and after; multiple sites | GP practices in 1 geographical area | GPs | 15 laboratory tests | TSH, FT4 |
| van Walraven et al,39 Canada | Retrospective interrupted time series; multiple sites | All private non-hospital-based laboratories in Ontario | Physicians ordering tests from non-hospital laboratories | 7 laboratory tests; 6 unaffected tests were chosen as controls | TSH, TT4, TT3 |
| Vidal-Trécan et al,40 France | Before and after; multiple sites | A network of 50 non-profit university hospitals in the Paris region | Physicians | TFTs only | TSH, TT4, TT3, FT3, FT4 |
| Willis and Datta,41 UK | Before and after; single site | Medical admissions unit at a district general hospital | Nurses | Three potentially inappropriately requested test sets: thyroid profile, lipid profile and coagulation screen | Thyroid profile (unspecified) |
| Wong et al,42 USA | Controlled study; single site | University teaching hospital | Physicians | TFTs, creatinine kinase and lactate dehydrogenase isoenzyme | TSH, TT4, TT3 |
ED, emergency department; FT3, free tri-iodothyronine; FT4, free thyroxine; GP, general practitioner; NHS, National Health Service; RCT, randomised controlled trial; TFTs, thyroid function tests; TgAb, thyroglobin antibody; TPOAb, thyroid peroxidase antibody; TRAb, thyrotropin receptor antibody; TRH, thyrotropin-releasing hormone test; TSH, thyroid-stimulating hormone; TT3, total tri-iodothyronine; TT4, total thyroxin.