Impact of haemolysis in accuracy of pt aptt

This step, based on a variety of manual activities, is the most vulnerable part of the total testing process and is a major component of the reliability and validity of results in haemostasis and constitutes the most important source of erroneous or un-interpretable results.

Published online Sep Sample collection issues might arise because of inexperience or time pressures when collectors are faced with a busy clinic and multiple collection requirements. The following chapters concern the sample collection and sequence of drawing blood.

The side effects of such factors of influence can be reduced by standardizing the pre-analytical process [ 4 — 6 ].

Hemolysis electrolytes

In haemostasis, even more than in other disciplines of biology, quality is determined by a pre-analytical step that encompasses all procedures, starting with the formulation of the medical question, and includes patient preparation, sample collection, handling, transportation, processing, and storage until time of analysis. The use of centrifuge breaks should also be avoided or monitored to avoid remixing of test samples, particularly if plasma is to be frozen, since there is a potential for hemolysis and platelet contamination, which may subsequently affect most hemostasis assays. This increased risk depends on the estrogen dose as well as the progestogen type of oral contraceptives [ 22 ]. The aims of this study were to determine the effect of hemolysis on PPT and APTT tests and to find the plasma hemoglobin cut-off point that could affect the test results. The blood samples next underwent further lysis by expelling with stronger pressure for a total of 4 to 5 times. Determination of plasma hemoglobin was with reference to a level of 0. The major recommendation therefore is that laboratories standardize to 1 citrate concentration and develop normal ranges appropriate for that concentration. This procedure is a modification of the method proposed by Arora et al[ 7 ] and was chosen because the most common cause of hemolysis is mechanical factors occurring during the venipuncture or transportation processes. Moreover, it is very important that the clinician and the laboratory exchange all relevant information as much as possible [ 25 ]. The aim of pre-anaesthetic screening, based on detailed patient interviews and on physical examination, is to identify patients with an increased risk of perioperative bleeding to minimise perioperative haemorrhagic complications.

Microparticles derived from maternal endothelial cells and platelets, and from placental trophoblasts may contribute to the procoagulant effect [ 19 ]. When storing plasma, the lower the freezer temperature, the longer the specimens can be maintained for future testing.

Under-filling may cause significant sample dilution and may also provide falsely prolonged clotting times due to the excess calcium-binding citrate present. Within the hospital, positive patient identification should follow institutional rules and will typically entail electronic or bar-code methods to reduce the risk of patient misidentification.

High absorbance will be caused by cell-free hemoglobin from hemolysis at wavelengths used by photo-optical method instruments. Age, sex, and patient diagnosis data were recorded from the job list form. These samples were labeled as group 1. Errors in preanalytical and analytical phases may interfere with the reliability of results.

Hemolysis glucose level

The accurate standardization of the pre-analytical phase is of pivotal importance for achieving reliable results of coagulation tests and should reduce the side effects of the influence factors. The aims of this study were to determine the effect of hemolysis on PPT and APTT tests and to find the plasma hemoglobin cut-off point that could affect the test results. For platelet function assays, treatment with drugs known to reversibly inhibit platelet function e. Quality control of this instrument was performed twice a day, in the morning and afternoon, using a plasma control from Sysmex and then once a day with pooled normal plasma. Results Haemolysis interference Haemolysed paired samples Forty pairs of samples spontaneous in vitro haemolysis versus nonhaemolysed were available and tested with all the reagents for PT, APTT and fibrinogen. All assays were performed according to the manufacturer's instructions. The work cannot be changed in any way or used commercially without permission from the journal. The blood samples next underwent further lysis by expelling with stronger pressure for a total of 4 to 5 times. Furthermore, water baths must be properly maintained to make certain they are not inadvertently maintained at a higher temperature because this may lead to deterioration of coagulation factor activities and spurious coagulation test results. For example, whole blood stored up to 24—48 hours prior to centrifugation has been reported as acceptable for many hemostasis tests although not for FV, FVIII, and protein S , 25 , 32 but other studies have reported significant changes in some test results over such time periods.

Open in new tab Appropriate Sample Collection, Processing, and Storage These are critical to the attainment of appropriate test results but are often neglected, overlooked, or poorly applied.

In case of primary haemostatic abnormalities, it is common to seek a cutaneo-mucous type of haemorrhage.

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