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Check out the new look and enjoy easier access to your favorite features Tuberculosis is an airborne disease with serious medical consequences. It is caused by the bacterium Mycobacterium tuberculosis, which belongs to a group of closely related organisms in the M tuberculosis complex. Once an individual is infected with it, the disease develops primarily in the lungs. Only the active form of tuberculosis is contagious, with signs and symptoms that include fatigue, fever, night sweats, chills, loss of appetite, unintentional weight loss, hemoptysis, shortness of breath, and cough that may last ≥3 weeks.1 Approximately 13 million Americans have a latent tuberculosis infection, which usually results when immunocompetent individuals are exposed to M tuberculosis.2 These individuals are not contagious, nor do they exhibit symptoms. However, latent tuberculosis may progress into an active case. Thus, screening for tuberculosis is a primary prevention tool that should be performed regularly. During 2013 through 2015, for the first time in 23 years, the incidence of tuberculosis cases leveled off after decreasing each year.3 The same data showed that the majority of individuals infected with tuberculosis were clustered in California, Florida, New York, and Texas. In light of the persistence of this curable pathogen, healthcare providers should advocate for increasing awareness and encouraging screening for tuberculosis infection in appropriate settings. Presently, the vast majority of clinics use the Mantoux test to screen for cases of tuberculosis. Injection Technique Proper injection technique is essential when testing for tuberculosis. The Mantoux test is administered in the intradermal layer of the volar aspect of the forearm approximately 4 inches below the antecubital area. The bevel edge of the needle should be facing up and then inserted to inject 0.1 mL of tuberculin purified protein derivative (PPD). Proper injection technique should produce a small elevation (wheal) at the injection site. A reaction occurs when both induration and erythema are present 48 to 72 hours after administration. The diameter of the induration is measured in millimeters at the widest part. Erythema without induration is not considered significant.4 A significant reaction indicates that a patient has been exposed to M tuberculosis recently or in the past, or has been vaccinated with bacilli-containing Calmette-Guerin vaccine, which is effective in up to 80% of those who receive it.5 The vaccine is routinely used in Europe and Latin America but not in the United States. A positive tuberculin skin test (TST) does not mean active disease is present. Likewise, a negative TST does not exclude tuberculosis infection completely. In addition, an adequate immune response to produce a positive TST will not occur in a person who is immunocompromised. Reading of the TST should be conducted within 48 to 72 hours. The provider should palpate for induration to ensure that only induration and not injection is being measured. An induration measuring ≥15 mm in greatest diameter indicates a positive test in individuals with no known risk factors for tuberculosis, an induration ≥10 mm indicates a positive test in recent arrivals from high-risk countries, and an induration ≥5 mm represents a positive test in an individual with HIV or immunosuppression, or someone who recently has been exposed to active tuberculosis.64 For many years, the Centers for Disease Control and Prevention (CDC) has emphasized the importance of implementing proper techniques for administration of the Mantoux test. More specifically, healthcare providers are advised to repeat the Mantoux test on the opposite arm if the initial PPD does not yield a wheal at the injected site.7 Common misconceptions exist among clinicians concerning the significance of creating a wheal when administering a TST. As an example, a newly graduated nurse posted comments in an online nursing forum seeking validation from other forum members concerning her experience administrating a TST on a patient without a resultant wheal (Table). Table. Responses Given by Forum Members
This article originally appeared on Clinical Advisor Intradermal injections (ID) are injections administered into the dermis, just below the epidermis. The ID injection route has the longest absorption time of all parenteral routes. These types of injections are used for sensitivity tests, such as TB (see Figure 7.13), allergy, and local anesthesia tests. The advantage of these tests is that the body reaction is easy to visualize, and the degree of reaction can be assessed. The most common sites used are the inner surface of the forearm and the upper back, under the scapula. Choose an injection site that is free from lesions, rashes, moles, or scars, which may alter the visual inspection of the test results (Lynn, 2011). Equipment used for ID injections is a tuberculin syringe calibrated in tenths and hundredths of a millilitre, and a 1/4 to 1/2 in., 26 or 27 gauge needle. The dosage of an ID injection is usually under 0.5 ml. The angle of administration for an ID injection is 5 to 15 degrees. Once the ID injection is completed, a bleb (small blister) should appear under the skin. Checklist 56 outlines the steps to administer an intradermal injection. Figure 7.13 TB syringe Checklist 56: Administering an Intradermal (ID) Injection
Subcutaneous InjectionsSubcutaneous (SC) injections are administered into the adipose tissue layer just below the epidermis and dermis. This tissue has few blood vessels, so drugs administered by this route have a slow, sustained rate of absorption. Sites for SC injections include the outer aspect of the upper arm, the abdomen (from below the costal margin to the iliac crest) within one inch of the belly button, anterior aspects of the thighs, upper back, and upper ventral gluteal area (Lynn, 2011) (see Figure 7.14). Figure 7.14 SC injection sitesChoose a site that is free of skin lesions and bony prominences. Site rotation prevents the formation of lipohypertrophy or lipoatrophy in the skin. Physical exercise or application of hot or cold compresses influences the rate of drug absorption by altering local blood flow to the tissues. Any condition that impairs that blood flow to the subcutaneous tissue contradicts the use of subcutaneous injections. Examples of subcutaneous medications include insulin, opioids, heparin, epinephrine, and allergy medication (Perry et al., 2014). To administer an SC injection, a 25 to 30 gauge, 3/8 in. to 5/8 in. needle is used. Some subcutaneous injections come prefilled with the syringe attached. Always confirm that the right-size needle is appropriate for the patient before use. Subcutaneous injections are usually given at a 45- to 90-degree angle. The angle is based on the amount of subcutaneous tissue present. Generally, give shorter needles at a 90-degree angle and longer needles at a 45-degree angle (Lynn, 2011). SC injections do not need to be aspirated as the likelihood of injecting into a blood vessel is small. Usually, no more than 1 ml of medication is given subcutaneously, as larger amounts may cause discomfort to the patient and may not be absorbed appropriately (Lynn, 2011). There are varying opinions on whether to pinch the skin during administration. Pinching is advised for thinner patients in order to lift the adipose tissue up and away from the underlying muscle and tissue. If pinching is used, release the pinch when the needle is inserted to avoid injecting into compressed tissue. Note, too, that elevating or pinching the skin has been found to increase the risk of injury, as the needle may pierce the opposite side of the skin fold and enter the skin of the health care worker (Black, 2013). The abdomen is the best location for an SC injection if a patient has little peripheral SC tissue. If patient is obese, use a needle that is long enough to insert through the tissue at the base of the skin fold (Perry et al., 2014). Insulin SC InjectionsInsulin is considered a high-risk medication, and special care must be taken to ensure the correct amount of medication and type of insulin is administered at the correct time. As well, safety checks related to a patient receiving SC insulin should be carried out (Ellis & Parush, 2012). Table 7.5 lists specific guidelines for administering insulin (and see Figure 7.15). Table 7.5 Guidelines for Administering SC Insulin
Special considerations:
Heparin SC InjectionsHeparin is an anticoagulant used to reduce the risk of thrombosis formation by suppressing clot formation (Perry et al., 2014). Heparin is also considered a high-alert medication (ISMP, 2014). Table 7.6 provides specific guidelines to consider before and after administering heparin.
Checklist 57 provides the steps to complete a subcutaneous injection. Checklist 57: Administering a Subcutaneous Injections
Video 7.3
Video 7.4Which route of administration should a medical assistant use when performing a tuberculin skin test?The injection should be placed on the palm-side-up surface of the forearm, about 2 to 4 inches below the elbow. Your local institutional policy may specify the right or the left forearm for the skin test.
When is the palpatory method performed?Palpatory method:. Empty air from the cuff and apply the cuff firmly around the patient's arm.. Feel the radial pulse.. Inflate the cuff until the radial pulse disappears.. Inflate 30-40 mm over and release slowly until the pulse returns. ... . Diastolic blood pressure cannot be obtained by this method.. Which of the following action should a medical assistant take when obtaining the length of an infant during a well child visit?Which of the following actions should a medical assistant take when obtaining the length of an infant during a well-child visit? Position the infant on his back. A medical assistant is reinforcing teaching about a cardiac event monitor with a patient.
Which of the following actions should a medical assistant take to verify the quality of a venipuncture supplies before beginning a blood draw?Which of the following actions should a medical assistant take to verify the quality of venipuncture supplies before beginning a blood draw? Inspect the integrity of the needle's seal.
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