Over-reporting significant figures--a significant problem?
BACKGROUND
Excessive use of significant figures in numerical data gives a spurious impression of laboratory imprecision to clinicians. We describe reporting practices in 24 Asia-Pacific laboratories, assess whether these reporting formats and those used in the literature can be justified based on actual laboratory performance and outline how to choose the appropriate number of significant places.


METHODS
Thirty-two laboratories in Asia-Pacific were surveyed as to their reporting practices for serum creatinine, ferritin, sodium and TSH. Imprecision data from the General Serum Chemistry program from the RCPA-AACB Quality Assurance Program (QAP) were used to assess whether the reporting unit magnitude implicitly suggested in Tietz, the RCPA Manual and the General Serum Chemistry program itself was justified.


RESULTS
There was a 75% response rate to the survey, with laboratories generally reporting data using unjustifiable deciles. Unit sizes from the RCPA manual, Tietz and the RCPA-AACB QAP were not justified by the majority of laboratories in the RCPA-AACB QAP.


CONCLUSIONS
The reporting unit size used by many laboratories is not justified by present laboratory performance using a 95% probability level. A consensus on appropriate reporting unit size is needed to encourage laboratories to change their present reporting formats.
Hawkins
Robert C
RC
Department of Pathology and Laboratory Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore. Robert_Hawkins@ttsh.com.sg
Badrick
Tony
T
Hickman
Peter E
PE
D001315:Australia; D002624:Chemistry, Clinical / Q000706:statistics & numerical data*; D003404:Creatinine / Q000097:blood; D003625:Data Collection; D005293:Ferritins / Q000097:blood; D007770:L-Lactate Dehydrogenase / Q000097:blood; D007753:Laboratories; D008433:Mathematics; D009520:New Zealand; D012107:Research Design / Q000706:statistics & numerical data*; D012846:Singapore; D012964:Sodium / Q000097:blood; D013972:Thyrotropin / Q000097:blood
D013972:Thyrotropin; D005293:Ferritins; D012964:Sodium; D003404:Creatinine; D007770:L-Lactate Dehydrogenase