***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The purpose of this study was to test agreement in blood values obtained from a discard method and a push-pull method in sample s from central venous catheters in pediatric patients . The discard method causes blood loss beyond what is necessary for blood testing and increases potential for infection each time the central venous catheter is entered . Twenty-eight children ranging in age from 6 months to 12 years were enrolled in the study . A research protocol was developed to pair the 2 methods of blood collection for each sample . The Bl and -Altman method was used to test agreement on each blood value for each paired sample . Of the 438 pairs of measured blood values , 420 ( 95.9 % ) fell within the limits of agreement . Nurses reported no difficulty in using the push-pull technique to obtain any sample s. The push-pull method of obtaining blood specimens from pediatric central venous catheters should be considered . It can eliminate blood loss through discard and can reduce infection because it reduces the number of times a catheter is entered Purpose / Objective : The purpose of this study was to test an evidence -based procedure of drawing blood sample s for coagulation testing from heparinized peripherally inserted central catheter ( PICC ) by comparing results with blood drawn from venipuncture ( VP ) . Design : A prospect i ve , quasi-experimental design using purposive sampling was used . Setting : The setting was a 230-bed community hospital located in the Southwest . The hospital is part of a 15-hospital system . Sample : The sample was composed of 30 hospitalized patients with heparinized PICCs . Methods : Informed consent was obtained . Using aseptic technique , sample s of blood were drawn via VP and from the PICC using the evidence -based procedure . Data were analyzed using Pearson product moment correlations and Bl and -Altman analysis . Findings : For 5 coagulation tests studied , correlations between PICC values and VP values ranged from 0.990 to 0.998 , indicating almost perfect correlations . In Bl and -Altman analyses , mean biases and SDs were small to moderate for prothrombin time , 0.13 seconds ( −0.55 to 0.81 seconds ) ( P = 0.0484 ) ; international normalized ratio , 0.010 ( −0.050 to 0.070 ) ( P = 0.085 ) ; partial thromboplastin time , 2.16 seconds ( −5.10 to 9.43 seconds ) ( P = 0.0033 ) ; and fibrinogen , −18.2 mg ( −70.4 to 34.1 mg ) ( P = 0.0033 ) and 0.52 ( −0.73 to 1.77 ) seconds ( P = 0.0003 ) . Correlations of absolute difference versus average ranged from 0.18 to 0.49 . Only the paired international normalized ratio sample s had P values suggesting nonagreement . Conclusions : Drawing blood sample s from heparinized PICCs for coagulation tests using the evidence -based procedure developed for this study result ed in accurate coagulation test results in 4 of the 5 tests : prothrombin time , partial thromboplastin time , and fibrinogen in seconds and in milligrams PURPOSE / OBJECTIVES Determine the blood volume that must be wasted to obtain a clinical ly useful prothrombin time ( PT ) , activated partial thromboplastin time ( APTT ) , and fibrinogen concentration for blood drawn from a heparinized ( 2.5 ml of 100 units/ml ) , double-lumen venous catheter . DESIGN Prospect i ve , nonr and omized study comparing test results obtained from blood sample s drawn through the catheters with those obtained via peripheral venipuncture . Patients acted as their own control . SETTING Inpatient and outpatient units of a cancer research center located in a mid-Atlantic city in the United States . SAMPLE Twenty double-lumen 10 Fr . Hickman catheters ( Bard Access Systems , Salt Lake City , UT ) were studied in 20 adult patients with cancer who had no history of coagulation disorders . METHODS Sample s were collected from the red lumen of 20 heparinized , double-lumen Hickman catheters after 5 , 10 , 15 , 20 , and 25 ml of blood first were discarded . PTs , APTTs , and fibrinogen concentrations were measured on each sample . The results were compared with those derived from a simultaneously obtained peripheral blood sample . MAIN RESEARCH VARIABLES PT , APTT , and fibrinogen values of blood sample s after 5 , 10 , 15 , 20 , and 25 ml discards and PT , APTT , and fibrinogen of peripheral blood sample s. FINDINGS The coagulation results using peripheral blood were always within the normal range except for one slightly elevated APTT . After 25 ml of discard , all of the PTs and fibrinogen concentrations and 95 % of the APTTs of catheter blood were within the normal range and therefore clinical ly useful . CONCLUSIONS Clinical ly useful PTs , APTTs , and fibrinogen concentrations often can be derived with catheter-drawn blood when the objective is to confirm normal coagulation . However , because it is very difficult to obtain heparin-free sample s through heparinized , double-lumen Hickman catheters , peripheral blood should be drawn for coagulation testing when a totally heparin-free sample is needed to make a critical clinical decision . IMPLICATION S FOR NURSING PRACTICE These findings provide important information for practice when nurses have to decide whether to draw coagulation tests through a heparinized catheter . Further research is needed with larger sample s in varied population s ( e.g. , pediatrics ) to study catheters made of different material s and of different calibers 
    Output:
    
FINDINGS The only method for obtaining reliable coagulation test results from central venous access devices is the flush then waste/discard method .