Editorials Metrication fror Crawl to Walk
Received and accepted October 30, 1975.
now. The situation is rapidly becoming intolerable, detrimental to progress in medicine, to the continuing education of physicians and allied health workers; and ultimately, of course, to the quality of patient care. Therefore, in the instructions on new editorial policy that appear in this issue, future contributors are requested to express results of laboratory tests in SI units, in parentheses, following the corresponding values in conventional units. We will continue to face problems, of course. Indeed, it has been necessary to list in the instructions to contributors those SI units that, for various reasons, we do not yet recommend. For example, acceptance of the proposed new unit of enzymic activity (the katal) has been very limited. Also, there is international agreement among hematologists not to convert, at this time, to expression of hemoglobin values in substance-concentration units. For similar reasons we cannot recommend expressing in substance-concentration units any substance with unknown or incompletely known molecular weights. We do not recommend abandonment of the traditional "milliosmoles per liter" expression; and believe that, in many instances, use of the unit "pH" may be preferable to use of the substance-concentration term for hydrogen ion. Finally, further work is needed on appropriate use of significant figures for values expressed in the new units. In spite of these caveats, it has clearly become our responsibility to take the lead in reuniting the presently separated halves of the world's medical literature, and we accept the responsibility. MYRTON F. BEELER,
M.D.
New Orleans, Louisiana References 1. Beeler MF, Copeland BE, Gambino SR, et al: T h e metric system and clinical chemistry. A m J Clin Pathol 59:277-281, 1973
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
in this issue, by Peter Lehmann, provides a summary of the development and general concept of the international metric system (SI), as well as a compilation of normal values of commonly assayed body constituents in conventional and in SI units and a list of conversion factors. We recommended in an editorial published in this journal nearly three years ago 1 that, after due consideration, we should initiate a change to use of the SI, concomitantly providing for an interim period during which results would be reported in both new units and conventional units. Since then, while Europe and Australia have galloped ahead, American medicine has been on the crawl. 2,3 In our opinion, the disadvantages of proceeding (which were discussed in our previous editorial and are discussed by Bradley Copeland in the editorial that follows this one) are now considerably outweighed by the disadvantages of not proceeding. American physicians are already finding their access to European medical journals—many of which are published in English—seriously hampered by unfamiliarity with the SI. Examples come readily to hand. In Ramus and Shorey's article on Crohn's disease, recently published in the British Medical Journal,4 a patient's serum bilirubin at time of hospital administration is given as 140 jU.mol/1. How many of our American readers immediately grasp the significance of this concentration? Toft and associates, in their recent article in The Lancet concerning thyroid function, 5 state that the sensitivity of the T3 assay was "0.25 nmol/1." How many of you, reading this in the United States, can readily assess the significance of this sensitivity? Europeans and Australians, on the other hand, as they forget normal values in conventional units, will likewise be losing access to our medical literature unless we take positive action T H E LEAD ARTICLE
20
A.J.C.P.—Vol.
EDITORIALS
2. Copeland BE, Beautyman W, Bradley R, et al: Study Committee to Evaluate Changes in Units of Clinical Chemistry Tests. N Engl J Med 293:20-44, 1975 3. Inglefinger FJ: Metrication on the crawl. N Engl J Med 292:806-807, 1975
65
4. Ramus MI, Shorey SA: Crohn's disease and psoas abscess. Br Med J 3:574-575, 1975 5. Toft ER, Irvine UJ, Seth J, et al: Thyroid function in the long-term followup of patients treated with iodine131 for thyrotoxicosis. The Lancet. 11:576-578, 1975
SI Units—A Clarification
Commission on World Standards World Association of Societies of Pathology Resolution No. 2: T o Clarify the Discussion of SI Units WHEREAS the general public as well as the Received and accepted November 14, 1975.
entire scientific community are urged to adopt the SI system of units moved that the Commission on World Standards (in order to clarify the understanding of the SI unit system) agrees (1) that both the mass concentration unit (g/L) and the substance concentration unit (mol/L) are included in the SI unit system (2) that it is not correct to imply that conversion to or adoption of the SI system requires the adoption of the mol concentration unit as the only concentration unit. B R A D L E Y E. C O P E L A N D ,
Boston,
M.D.
Massachusetts
EDITOR'S N O T E T H E MEMBERS of t h e B o a r d of Editors have u r g e d t h a t t h e I n t e r n a t i o n a l Metric System (SI) be i n t r o d u c e d in t h e American Journal of Clinical Pathology in o r d e r to familiarize o u r r e a d e r s with SI a n d to m a k e the J o u r n a l m o r e r e a d a b l e in c o u n t r i e s now u s i n g SI. I n the n e a r f u t u r e in t h e A J C P , q u a n t i t a tive m e a s u r e m e n t s in t h e conventional units will be followed by SI in p a r e n t h e s e s . T h i s will apply to quantitative m e a s u r e m e n t s with t h e exception oipH, gas p r e s s u r e m e a s u r e m e n t s (P 0 2 a n d Pco2)> a n d osmolality, w h e r e t h e c u r r e n t l y used units m a y be r e t a i n e d . All c o n c e n t r a t i o n s s h o u l d be based o n a v o l u m e of o n e liter a n d a m o u n t s e x p r e s s e d as moles e x c e p t in those cases w h e r e definite m o l e c u l a r weights have n o t b e e n established, e.g. p r o t e i n s , a n d m i x t u r e s , w h e r e the use of SI units is o p tional. C o n v e r s i o n may be c a r r i e d o u t u s i n g factors given in Dr. L e h m a n n ' s p a p e r . Presently used e n z y m e units s h o u l d be r e t a i n e d . A u t h o r s a r e u r g e d to s u b m i t their m a n u scripts in this f o r m h e n c e f o r t h . FRANK VELLIOS,
Editor
M.D.
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
T H E GRAM a n d milligram ARE decimally related SI units. Only t h e kilogram is an SI unit. C u r r e n t units, such as g r a m p e r liter, milligram p e r deciliter, a r e SI related units. " A d o p t i o n of SI u n i t s " d o e s not m e a n c o m p u l s o r y a d o p t i o n of m o l e c u l a r conc e n t r a t i o n units. Mass c o n c e n t r a t i o n units a n d molecular c o n c e n t r a t i o n units a r e BOTH SI r e lated units. T h e C o n f e r e n c e G e n e r a l d e Poids et M e s u r e (CGPM) has not r e c o m m e n d e d that clinical chemistry units be c h a n g e d from mass c o n c e n t r a t i o n to m o l e c u l a r c o n c e n t r a t i o n . O n l y t h e C G P M can issue official s t a t e m e n t s r e g a r d i n g SI units. T h e official U.S. publication is N B S Special Publication # 3 3 0 , T h e I n t e r n a tional System of Units (SI), 1974. Dr. C. H . Page (NBS USA) is C o o r d i n a t o r for I n t e r n a t i o n a l S t a n d a r d i z a t i o n Activities. D r . E. A m b l e r is t h e U . S . m e m b e r of C G P M . S o m e g r o u p s , both national a n d international, r e c o m m e n d molecularization of all clinical chemistry units. O t h e r g r o u p s d i s a g r e e with this for various reasons. D i s a g r e e m e n t is consistent with scientific discussion. T o imply t h a t only SI molecular units a r e acceptable u n d e r t h e SI system is incorrect a n d unscientific. At the N i n t h World C o n g r e s s of Societies of Pathology, Sydney, Australia, 1975, t h e following resolution was a d o p t e d by t h e Commission on World S t a n d a r d s .
Received and accepted October 30, 1975.
now. The situation is rapidly becoming intolerable, detrimental to progress in medicine, to the continuing education of physicians and allied health workers; and ultimately, of course, to the quality of patient care. Therefore, in the instructions on new editorial policy that appear in this issue, future contributors are requested to express results of laboratory tests in SI units, in parentheses, following the corresponding values in conventional units. We will continue to face problems, of course. Indeed, it has been necessary to list in the instructions to contributors those SI units that, for various reasons, we do not yet recommend. For example, acceptance of the proposed new unit of enzymic activity (the katal) has been very limited. Also, there is international agreement among hematologists not to convert, at this time, to expression of hemoglobin values in substance-concentration units. For similar reasons we cannot recommend expressing in substance-concentration units any substance with unknown or incompletely known molecular weights. We do not recommend abandonment of the traditional "milliosmoles per liter" expression; and believe that, in many instances, use of the unit "pH" may be preferable to use of the substance-concentration term for hydrogen ion. Finally, further work is needed on appropriate use of significant figures for values expressed in the new units. In spite of these caveats, it has clearly become our responsibility to take the lead in reuniting the presently separated halves of the world's medical literature, and we accept the responsibility. MYRTON F. BEELER,
M.D.
New Orleans, Louisiana References 1. Beeler MF, Copeland BE, Gambino SR, et al: T h e metric system and clinical chemistry. A m J Clin Pathol 59:277-281, 1973
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
in this issue, by Peter Lehmann, provides a summary of the development and general concept of the international metric system (SI), as well as a compilation of normal values of commonly assayed body constituents in conventional and in SI units and a list of conversion factors. We recommended in an editorial published in this journal nearly three years ago 1 that, after due consideration, we should initiate a change to use of the SI, concomitantly providing for an interim period during which results would be reported in both new units and conventional units. Since then, while Europe and Australia have galloped ahead, American medicine has been on the crawl. 2,3 In our opinion, the disadvantages of proceeding (which were discussed in our previous editorial and are discussed by Bradley Copeland in the editorial that follows this one) are now considerably outweighed by the disadvantages of not proceeding. American physicians are already finding their access to European medical journals—many of which are published in English—seriously hampered by unfamiliarity with the SI. Examples come readily to hand. In Ramus and Shorey's article on Crohn's disease, recently published in the British Medical Journal,4 a patient's serum bilirubin at time of hospital administration is given as 140 jU.mol/1. How many of our American readers immediately grasp the significance of this concentration? Toft and associates, in their recent article in The Lancet concerning thyroid function, 5 state that the sensitivity of the T3 assay was "0.25 nmol/1." How many of you, reading this in the United States, can readily assess the significance of this sensitivity? Europeans and Australians, on the other hand, as they forget normal values in conventional units, will likewise be losing access to our medical literature unless we take positive action T H E LEAD ARTICLE
20
A.J.C.P.—Vol.
EDITORIALS
2. Copeland BE, Beautyman W, Bradley R, et al: Study Committee to Evaluate Changes in Units of Clinical Chemistry Tests. N Engl J Med 293:20-44, 1975 3. Inglefinger FJ: Metrication on the crawl. N Engl J Med 292:806-807, 1975
65
4. Ramus MI, Shorey SA: Crohn's disease and psoas abscess. Br Med J 3:574-575, 1975 5. Toft ER, Irvine UJ, Seth J, et al: Thyroid function in the long-term followup of patients treated with iodine131 for thyrotoxicosis. The Lancet. 11:576-578, 1975
SI Units—A Clarification
Commission on World Standards World Association of Societies of Pathology Resolution No. 2: T o Clarify the Discussion of SI Units WHEREAS the general public as well as the Received and accepted November 14, 1975.
entire scientific community are urged to adopt the SI system of units moved that the Commission on World Standards (in order to clarify the understanding of the SI unit system) agrees (1) that both the mass concentration unit (g/L) and the substance concentration unit (mol/L) are included in the SI unit system (2) that it is not correct to imply that conversion to or adoption of the SI system requires the adoption of the mol concentration unit as the only concentration unit. B R A D L E Y E. C O P E L A N D ,
Boston,
M.D.
Massachusetts
EDITOR'S N O T E T H E MEMBERS of t h e B o a r d of Editors have u r g e d t h a t t h e I n t e r n a t i o n a l Metric System (SI) be i n t r o d u c e d in t h e American Journal of Clinical Pathology in o r d e r to familiarize o u r r e a d e r s with SI a n d to m a k e the J o u r n a l m o r e r e a d a b l e in c o u n t r i e s now u s i n g SI. I n the n e a r f u t u r e in t h e A J C P , q u a n t i t a tive m e a s u r e m e n t s in t h e conventional units will be followed by SI in p a r e n t h e s e s . T h i s will apply to quantitative m e a s u r e m e n t s with t h e exception oipH, gas p r e s s u r e m e a s u r e m e n t s (P 0 2 a n d Pco2)> a n d osmolality, w h e r e t h e c u r r e n t l y used units m a y be r e t a i n e d . All c o n c e n t r a t i o n s s h o u l d be based o n a v o l u m e of o n e liter a n d a m o u n t s e x p r e s s e d as moles e x c e p t in those cases w h e r e definite m o l e c u l a r weights have n o t b e e n established, e.g. p r o t e i n s , a n d m i x t u r e s , w h e r e the use of SI units is o p tional. C o n v e r s i o n may be c a r r i e d o u t u s i n g factors given in Dr. L e h m a n n ' s p a p e r . Presently used e n z y m e units s h o u l d be r e t a i n e d . A u t h o r s a r e u r g e d to s u b m i t their m a n u scripts in this f o r m h e n c e f o r t h . FRANK VELLIOS,
Editor
M.D.
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
T H E GRAM a n d milligram ARE decimally related SI units. Only t h e kilogram is an SI unit. C u r r e n t units, such as g r a m p e r liter, milligram p e r deciliter, a r e SI related units. " A d o p t i o n of SI u n i t s " d o e s not m e a n c o m p u l s o r y a d o p t i o n of m o l e c u l a r conc e n t r a t i o n units. Mass c o n c e n t r a t i o n units a n d molecular c o n c e n t r a t i o n units a r e BOTH SI r e lated units. T h e C o n f e r e n c e G e n e r a l d e Poids et M e s u r e (CGPM) has not r e c o m m e n d e d that clinical chemistry units be c h a n g e d from mass c o n c e n t r a t i o n to m o l e c u l a r c o n c e n t r a t i o n . O n l y t h e C G P M can issue official s t a t e m e n t s r e g a r d i n g SI units. T h e official U.S. publication is N B S Special Publication # 3 3 0 , T h e I n t e r n a tional System of Units (SI), 1974. Dr. C. H . Page (NBS USA) is C o o r d i n a t o r for I n t e r n a t i o n a l S t a n d a r d i z a t i o n Activities. D r . E. A m b l e r is t h e U . S . m e m b e r of C G P M . S o m e g r o u p s , both national a n d international, r e c o m m e n d molecularization of all clinical chemistry units. O t h e r g r o u p s d i s a g r e e with this for various reasons. D i s a g r e e m e n t is consistent with scientific discussion. T o imply t h a t only SI molecular units a r e acceptable u n d e r t h e SI system is incorrect a n d unscientific. At the N i n t h World C o n g r e s s of Societies of Pathology, Sydney, Australia, 1975, t h e following resolution was a d o p t e d by t h e Commission on World S t a n d a r d s .
