Laboratory Control of Coumarin Therapy

doi:10.1059/0003-4819-57-4-572

Laboratory Control of Coumarin Therapy

The Clinician's Dilemma

MORRIS J. SEIDE, M.D.

Requests for reprints should be addressed to Morris J. Seide, M.D.,
85 Jefferson Street, Hartford, Connecticut
.

Excerpt

Since their introduction into clinical medicine 20 years ago (1), coumarin drugs have become widely used. In the past 10 years, the number of patients maintained on long-term therapy has increased phenomenally. In the Hartford area, the clinical laboratories now perform about 500, and the hospital laboratories about 1,200 prothrombin tests each week, serving a population of about 350,000.

The prothrombin test devised some 25 years ago by Quick (2) is widely used by clinicians as a guide to the dose of coumarin drug to be prescribed. This test is a bio-assay which requires meticulous technique, experienced technicians, and reliable

Summario in Interlingua

Le "test pro prothrombina" de Quick es extensemente usate pro determinar le dosage de coumarina a prescriber. Le test es un bio-essayo que require un meticulose technica, experientiate technicos, e reagentes con alte standards de fidelitate. Plus que un laboratorio participa, in frequente casos, in le guarda del patiente individual, proque usualmente le tractamento comencia al hospital durante un episodio acute del morbo e continua subsequentemente a base de un servicio pro patientes visitante.

Pro determinar le validitate, reproducibilitate, a fidelitate del test e pro comparar le resultatos de differente laboratorios, sanguines esseva prendite ab 30 patientes in varie stadios de therapia a coumarina. Quaranta-cinque millilitros de sanguine esseva addite a 5 ml de oxalato. Le combination esseva centrifugate. Le plasma esseva decanthate, miscite, e dividite in portiones de 0,7 ml. Un medietate de cata plasma esseva identificate per un codice numeric, le altere per un altere. Postea le material esseva distribuite inter le 13 collaborante laboratorios pro tests e reportos a base del usual routine. Commercialmente obtenibile plasmas de controlo e uniforme thromboplastinas esseva similemente distribuite. Le resultatos divergeva extensemente, non solmente ab un laboratorio al altere sed etiam intra le laboratorios individual.

Le major causas de iste discrepantias pareva esser contribuite per le curvas de diluente a base del quales le "procentage" es determinate, per le diluente e le technicas usate in preparar le curvas de dilution, per le uso de varie typos de thromboplastina, per modificationes in le technica, per errores technic, per le prolongation del tempore pro le banio de aqua, e per differentias in le temperatura del banio de aqua.

Proponimentos visante a corriger iste discrepantias include le elimination del curvas de dilution, le reportage del resultatos como secundas e como proportiones, le adoption de un uniforme e meticulose technica, le trainamento e frequente inspection del technicos, le uso de vitralias standard, le regulation del temperatura, uniformitate del thromboplastina, regulation de anticoagulante per le laboratorio, e tests periodic de non-cognoscite plasmas.