Đang tải... (xem toàn văn)
(BQ) Part 1 book Concise book of medical laboratory technology - Methods and interpretations presents the following contents: Laboratory, fundamental chemistry, urine analysis, renal function and its evaluation, clinical hematology, medical parasitology, stool examination, semen analysis, sputum examination,...
Concise Book of Medical Laboratory Technology Methods and Interpretations Concise Book of Medical Laboratory Technology Methods and Interpretations 2nd Edition Ramnik Sood MD (Path, Gold Medalist) Consultant Reem Medical and Diagnostic Center Healthcare Mena Limited Sharjah United Arab Emirates The Health Sciences Publisher New Delhi | London | Philadelphia | Panama Jaypee Brothers Medical Publishers (P) Ltd Headquarters Jaypee Brothers Medical Publishers (P) Ltd 4838/24, Ansari Road, Daryaganj New Delhi 110 002, India Phone: +91-11-43574357 Fax: +91-11-43574314 Email: jaypee@jaypeebrothers.com Overseas Offices J.P Medical Ltd 83 Victoria Street, London SW1H 0HW (UK) Phone: +44 20 3170 8910 Fax: +44 (0)20 3008 6180 Email: info@jpmedpub.com Jaypee-Highlights Medical Publishers Inc City of Knowledge, Bld 237, Clayton Panama City, Panama Phone: +1 507-301-0496 Fax: +1 507-301-0499 Email: cservice@jphmedical.com Jaypee Medical Inc The Bourse 111 South Independence Mall East Suite 835, Philadelphia, PA 19106, USA Phone: +1 267-519-9789 Email: jpmed.us@gmail.com Jaypee Brothers Medical Publishers (P) Ltd 17/1-B Babar Road, Block-B, Shaymali Mohammadpur, Dhaka-1207 Bangladesh Mobile: +08801912003485 Email: jaypeedhaka@gmail.com Jaypee Brothers Medical Publishers (P) Ltd Bhotahity, Kathmandu, Nepal Phone: +977-9741283608 Email: kathmandu@jaypeebrothers.com Website: www.jaypeebrothers.com Website: www.jaypeedigital.com © 2015, Ramnik Sood The views and opinions expressed in this book are solely those of the original contributor(s)/author(s) and not necessarily represent those of editor(s) of the book All rights reserved No part of this publication may be reproduced, stored or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission in writing of the publishers All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners The publisher is not associated with any product or vendor mentioned in this book Medical knowledge and practice change constantly This book is designed to provide accurate, authoritative information about the subject matter in question However, readers are advised to check the most current information available on procedures included and check information from the manufacturer of each product to be administered, to verify the recommended dose, formula, method and duration of administration, adverse effects and contraindications It is the responsibility of the practitioner to take all appropriate safety precautions Neither the publisher nor the author(s)/editor(s) assume any liability for any injury and/or damage to persons or property arising from or relate♥d to use of material in this book This book is sold on the understanding that the publisher is not engaged in providing professional medical services If such advice or services are required, the services of a competent medical professional should be sought Every effort has been made where necessary to contact holders of copyright to obtain permission to reproduce copyright material If any have been inadvertently overlooked, the publisher will be pleased to make the necessary arrangements at the first opportunity Inquiries for bulk sales may be solicited at: jaypee@jaypeebrothers.com Concise Book of Medical Laboratory Technology: Methods and Interpretations First Edition: 2009 Second Edition: 2015 ISBN 978-93-5152-333-8 Printed at Dedicated to the Readers Preface to the Second Edition I authored an exhaustive book entitled “Medical Laboratory Technology – Methods and Interpretations” that hit the stands in mid-eighties in the previous century and is now running in its 6th edition This was the first such book in the subcontinent and was much appreciated and used by technologists and pathologists alike The book has seen testimonies in courts and has been appreciated in the west too However, in our subcontinent, I was requested by many technologists that they wanted a little younger sister of the book popularly known as MLT authored by me And so was born the Concise Book of Medical Laboratory Technology: Methods and Interpretations The book essentially covers everything presented in MLT-6 but in an abridged/shortened and easy-to-digest format The book is presented in a flowing noninterrupted format and not in a cumbersome experiment-wise cascading flow There is no break in the style that runs smoothly and is easier to absorb and assimilate As experiments are a part of any course, more stress has been laid out in the book to understand the intricacies of relevant theories and even troubleshooting all experiments that you would conduct during the course of your study As I have written multiple modules for many Universities in India, I did not have to think for too long to devise a style and format for this book You will find everything from ESR to PCR and you will find foam test for bile pigments as also complete automation in urinalysis You will find basic biochemistry as also detailed cytogenetics So whatever be your course or query, you will find it within the covers of this short but sweet book now going into its second edition The book is designed for you not to mug but to understand and elicit the answers from the book of all questions in your mind I am aware that this book is used by most of your teachers and tutors too Nothing wrong that you are holding now It will help you all your life! Ramnik Sood Preface to the First Edition The first book on Medical Laboratory Technology from the house of Jaypee’s came out in 1985 and has been the best seller in its class till date The title “Medical Laboratory Technology – Methods and Interpretations” has seen editions The latest one hit the stands in January this year and was released in two volumes It is a four-color book and has over 1670 pages The reader base of all editions of our vastly popular title “MLT” has been upcoming laboratorians, undergraduate and postgraduate medical students It was requested by a few institutes to produce a little smaller version of the two-volume set that would be suitable for the upcoming Laboratory Technology students So here it is! It is exhaustive yet precise and concise too The book will help you to appreciate things as they appear in real life under the microscope and otherwise All current technologies find a mention within the covers of this book Gone are the days when we had to prepare reagents first thing in the morning (or the days usage); therefore, the current trend of consuming ready-to-use reagents/kits is followed here to make your job and understanding simpler So, what is available in the market for all investigations, is what is presented here The Tulip Group has very kindly given us the rights to reproduce the text related to all their kits and reagents in this book Latest instruments are not forgotten too Most important— Parasitology section is presented in ample detail as it is relevant to all the developing nations Quality control/assurance is mentioned in appropriate details Working is not enough Working properly and producing nothing but the most accurate reports are the order of the day This book will not fail you there Follow the recommendations to the hilt and you would be running the most accurate laboratory available anywhere Should problems arise! The book has “Troubleshooting” section for every possible test mentioned inside If this happens – then what! If that happens – then what! You will find all answers From ESR to PCR – you will find everything The book is based on most syllabi as applicable to most institutes in India and elsewhere internationally All necessary care has been taken to weed out any discrepancies/typographical errors at the time of going to press However, if anything has remained inadvertently, the publishers/author not take any responsibility for the same in any manner whatsoever Learning can be enjoyable experience, flip a few pages to experience that Ramnik Sood CHAPTER 21 Blood Gases and Electrolytes BLOOD GASES Introduction Reasons for obtaining blood gases: Assessment of adequacy of oxygenation Assessment of adequacy of ventilation Assessment of acid-base status by measuring the respiratory and non-respiratory components Reasons for using arterial blood rather than venous blood to measure blood gases: Arterial blood is a good way to sample a mixture of blood that has come from various parts of the body a Venous blood in an extremity gives information mostly about that extremity The metabolism in the extremity can differ from the metabolism in the body as a whole This difference is accentuated i In shock, when the extremity is cold or under perfused ii With local exercise of extremity, as opening and closing the fist iii In local infection of the extremity b Blood from a central venous catheter usually is an incomplete mix of venous blood from various parts of the body For a sample of completely mixed blood, a sample would have to be obtained from the right ventricle or pulmonary artery, and even then information is not obtained about how well the lungs are oxygenating the blood Arterial blood gives the added information of how well the lungs are oxygenating the blood a If it is known that arterial O2 concentration is normal (indicating that the lungs are functioning normally), but the mixed venous O2 concentra- tion is low, it can be inferred that the heart and circulation are failing b Oxygen measurements of central venous catheter blood can tell if the tissues are getting oxygenated, but they not separate the contribution of the heart from the lungs If central venous catheter blood has a low O2 concentration, it means either that: i The lungs have not oxygenated the arterial blood well, so that venous blood has a low concentration, or ii The heart is not circulating the blood well In this case, the tissues of the body must take more than the usual amount of O2 from each cardiac cycle because the blood is flowing slowly This produces a low venous O2 concentration Note: The site of arterial puncture must satisfy three requirements: Available collateral blood flow Superficial or easily accessible Periarterial tissues (should be nonsensitive) The radial artery satisfies the criteria tested above, although the brachial and femoral are also arteries of choice Procedure for Obtaining Arterial Blood Sample Place the patient either in a sitting or supine position Elevate the wrist with a small pillow and ask the patient to extend fingers downward (this will flex the wrist and move the radial artery closer to the surface) Palpate the artery and rotate the patient’s hand back and forth until a good strong pulse is felt Blood Gases and Electrolytes Swab the area liberally with an antiseptic agent such as betadine Optional: Anesthetize the area with a small amount of 1% xylocaine (approximately ¼ mL or less) This allows a second attempt without undue pain if the first attempt is a failure Using a 20- or 21-gauge needle, make the puncture and then attach the preheparinized 12 mL syringe once the artery has been entered Pull the plunger on the syringe (being careful not to accidentally pull the needle out of the artery) and collect a to mL sample Withdraw needle and place a 4” × 4” absorbent bandage over the puncture site and maintain pressure with two fingers for a minimum of minutes Meanwhile, any air-bubbles in the blood sample should be expelled as quickly as possible; the syringe should be capped and gently rotated to mix heparin with blood 10 If the sample is not going to be analyzed for 15–20 minutes, place it in an icewater container until it can be analyzed Clinical Alert c s Capillary blood Shunted blood Combination of Symbols PO2 PvO2 = Oxygen tension or partial pressure of oxygen = Venous oxygen tension or partial pressure of oxygen in venous blood PaO2 = Arterial oxygen tension or partial pressure of oxygen in arterial blood PCO2 = Partial pressure of carbon dioxide PaCO2 = Partial pressure of carbon dioxide in arterial blood PvCO2 = Partial pressure of carbon dioxide in venous blood SO2 = Oxygen saturation SaO2 = Percent saturation of oxygen in arterial blood SvO2 = Percent saturation of oxygen in venous blood TCO2 = Total carbon dioxide content Blood Gases, Arterial (ABG) Blood Normal Values Must be corrected for body temperature SI units Arterial gases will not indicate to what degree the patient is suffering from an abnormality For this reason, the vital signs and mental function of the patient must be used as guides to determine adequacy of tissue oxygenation Arterial puncture site must have pressure applied and be watched carefully for bleeding Blood for gases (and electrolytes) must be drawn without trauma and be protected from room air at all times Be aware that air bubbles in the syringe will also change gas values pH Blood Gas Symbols Large capital letters are used as primary symbols for blood C = Concentration of gas in blood S = Percent saturation of hemoglobin with CO2 or O2 Q = Volume of blood QT = Volume of blood per unit time P = Gas pressure or partial pressure of a gas in a gas mixture or in blood To indicate whether blood is capillary, venous, arterial, lower case letters are used as subscripts: v = Venous blood a = Arterial blood = = 549 Adults 7.35–7.45 7.35–7.45 Panic values < 7.2 and > 7.6 < 7.2 and > 7.6 Birth–2 months 7.32–7.49 7.32–7.49 months–2 years 7.34–7.46 7.34–7.46 Over years 7.35–7.45 7.35–7.45 PaCO2 35–45 mm Hg 4.7–6.0 kPa Panic values < 20 mm Hg < 2.7 kPa PaO2 75–100 mm Hg 10.0–13.3 kPa Panic values < 40 mm Hg < 5.3 kPa HCO3 22–26 mEq/L 22–26 mmol/L Panic values < 10 mEq/L < 10 mmol/L O2 saturation 96–100% 0.96–1.00 Panic values < 60% < 0.60 Children Oxyhemoglobin dissociation Curve No shift Blood Gases, Capillary Blood Normal Values Must be corrected for body temperature 550 Concise Book of Medical Laboratory Technology: Methods and Interpretations SI units pH Adults 7.35–7.45 7.35–7.45 Panic values < 7.2 or > 7.6 < 7.2 or > 7.6 Children (arterialized capillary sample) Birth–2 months 7.32–7.49 7.32–7.49 months–2 years 7.34–7.46 7.34–7.46 Over years 7.35–7.45 7.35–7.45 PCO2 26.4–41.2 mm Hg 3.5–5.4 kPa Panic values < 20 mm Hg < 2.7 kPa > 70 mm Hg PO2 75–100 mm Hg 10.0–13.3 kPa Panic values < 40 mm Hg < 5.3 kPa HCO3 22–26 mEq/L 22–26 mmol/L Panic values < 10 mEq/L < 10 mmol/L O2 saturation 96–100% 0.96–1.00 Panic value < 60% < 0.60 Oxyhemoglobin Dissociation Curve No shift Blood gases interpretation Blood Gases, Venous Blood Normal Values Must be corrected for body temperature Blood Gases, Capillary Blood SI units Normal Values pH 7.32–7.43 7.32–7.43 Must be corrected for body temperature Panic value < 7.2 or > 7.6 < 7.2 or > 7.6 PCO2 38–50 mm Hg 5.0–6.7 kPa PO2 20–49 mm Hg 2.6–6.5 kPa HCO3 22–26 mEq/L 22–26 mmol/L Panic value < 10 mEq/L < 10 mmol/L > 40 mEq/L > 40 mEq/L 60–80% 0.60–0.80 SI Units pH Adults 7.35-7.45 7.35-7.45 Panic Values 7.6 7.6 Children (arterialized capillary sample) Birth-2 months 7.32-7.49 7.32-7.49 months-2 years 7.34-7.46 7.34-7.46 Over years 7.35-7.45 7.35-7.45 PCO2 26.4-41.2 mm Hg 3.5-5.4 kPa Panic values