Sputum Gram stain

定义

A sputum Gram stain is a laboratory test used to detect bacteria in a sputum sample. Sputum is the material that comes up from your air passages when you cough very deeply.

的 革兰氏染色法 is one of the most commonly used methods to rapidly identify the type of bacteria in a bacterial infection, including pneumonia.

选择的名字

Gram stain of sputum

How the Test is Performed

A sputum sample is needed.

• You will be asked to cough deeply and spit any substance that comes up from your lungs (sputum) into a special container.
• You may be asked to breathe in a mist of salty steam. This makes you cough more deeply and produce sputum.
• If you still do not produce enough sputum, you might have a procedure called 支气管镜检查.
• To increase the accuracy, this test is sometimes done 3 times, often 3 days in a row.

的 sample is sent to a lab. 的 lab team member places a very thin layer of the sample onto a glass slide. This is called a smear. Stains are placed on the sample. 的 lab team member looks at the stained slide under a microscope, checking for bacteria and white blood cells. 的 color, size, and shape of the cells help identify the bacteria.

How to Prepare for the Test

Drinking fluids the night before the test may help your lungs produce phlegm. It makes the test more accurate if it is done first thing in the morning.

If you are having a 支气管镜检查, follow your provider's instructions on how to prepare for the procedure.

How the Test will Feel

的re is no discomfort, unless a 支气管镜检查 needs to be performed.

Why the Test is Performed

Your health care provider may order this test if you have a persistent or prolonged cough, or if you are coughing up material that has a foul odor or unusual color. 的 test may also be done if you have other signs and symptoms of respiratory disease or infection.

正常的结果

A normal result means that few to no white blood cells and no bacteria were seen in the sample. 的 sputum is clear, thin, and odorless.

What Abnormal Results Mean

An abnormal result means that bacteria are seen in the test sample. You may have a bacterial infection. A culture is needed to confirm the diagnosis.

风险

的re are no risks, unless 支气管镜检查 is performed.

参考文献

Dockrell DH, Ho A, Gordon SB. Community-acquired pneumonia. In: Broaddus VC, Ernst JD, King TE, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine. 7日艾德. Philadelphia, PA: Elsevier; 2022:chap 46.

Plourde AR, Beavis KG. Specimen collection and handling for diagnosis of infectious diseases. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 66.