HOW DO YOU READ A GRAM STAINING OF A SPUTUM? And Interpret the results for better clinical care?
A question to post graduates in University examination in European union
Answered by Dr.T.V.Rao. MD
Today the world is moving towards the Clinical Microbiology unless we being active on clinical matters the reporting may go wary and it is utmost important in examination of sputum which is fraught with errors and observer variations but never forget to create standard operative procedures in collection of sputum and passed on to the paramedics for better ways to collect,
Instruction to collect the sputum by patients
Advice to Brush teeth and rinse mouth. Don’t use antiseptic mouthwash.
Take a couple of long, deep breaths. Then breathe deeply and cough hard until sputum comes up.
Spit out the sputum into sample cup. Keep coughing up sputum until the cup is filled to the marker, which should equal approximately 1 teaspoon.
Screw the lid onto the cup and wash and dry the outside of it. Write name and the date on the label.
Take the sample to the clinic or laboratory, following instruction. You can refrigerate it for up to 24 hours if needed, but you shouldn’t freeze it or store it at room temperature.
LABORATORY EXAMINATION OF SPUTUM FOR GRAM’S STAINING -
Discovered by Dr. Hans Christian Gram in 1884, the Gram stain is a differential stain that is used in identifying bacteria. Dividing bacterial cells in two major groups (Gram positive and Gram negative), gram staining is an important test used because it can determine the presence of bacteria in a sample, as well as differentiate between the two-distinct bacteria species, which are gram-positive and gram-negative bacteria. This test also is especially important in medicine because the identification of the specific pathogen can help in the treatment of a bacterial infection, in emergency hours, I always teach Gram staining continues to be an important primitive test stood the test of time and continues to be the only rapid test in Bacteriology, in most developing countries
SENSITIVITY AND SPECIFICITY – The early chapters in immunology we all have learnt on sensitivity and septicity; however, we must learn to apply the same terms in reporting the results from a sputum examination. The sensitivity of a technique usually depends on the number of microorganisms in the specimen. Its specificity depends on how morphologically unique a specific microorganism appears microscopically or how specific the antibody or genetic probe is for that genus or species. For example, the sensitivity of Cram stains is such that the observation of two bacteria per oil immersion field (X 1,000) of a Gram-stained smear. of uncentrifuged urine is equivalent to the presence of ≥ 105 CFU/ml of urine. An increase in the sensitivity of a test is often accompanied by a decrease in specificity. For example, examination of a Gram-stained smear of sputum from a patient with pneumococcal pneumonia is highly sensitive but also highly nonspecific if the criterion for defining a positive test is the presence of any Gram-positive cocci. If, however, a positive test is defined as the presence of a preponderance of Gram-positive, lancet-shaped diplococci, the test becomes highly specific but has a sensitivity of only about 50 percent, here we all differ with many of our colleagues when the sensitivity of the test become 50% or less the observer variations differs, and lead to conflicts, The identification of most Gram-negative bacilli is far more complex and often requires panels of many tests for determining biochemical and physiologic characteristics. Here comes the importance of clinical Microbiologists who are in constant touch with clinicians can be able to make a better diagnosis. The sensitivity may also be affected by the stage of the disease at which the specimen is collected. No gram stain observations are final in majority of specimens to be supported by a GOOD CLINICAL HISTORY culturing on Media suiting the facilities in the laboratory and doing a Antibiograms for the optimal results in clinical care.
CAUTION – Every Clinical sample has many reasons to be infected with Parasites, Viruses, and Fungi however the Grams method of staining is simple, economical and faster if used with wisdom.
Ref Principles of Diagnosis John A. Washington. Medical Microbiology. 4th edition.
Dr.T.V.Rao MD Freelance Clinical Microbiologist and on line educator
Please contact on collaborative work
Email – doctortvrao@gmail.com
A question to post graduates in University examination in European union
Answered by Dr.T.V.Rao. MD
Today the world is moving towards the Clinical Microbiology unless we being active on clinical matters the reporting may go wary and it is utmost important in examination of sputum which is fraught with errors and observer variations but never forget to create standard operative procedures in collection of sputum and passed on to the paramedics for better ways to collect,
Instruction to collect the sputum by patients
Advice to Brush teeth and rinse mouth. Don’t use antiseptic mouthwash.
Take a couple of long, deep breaths. Then breathe deeply and cough hard until sputum comes up.
Spit out the sputum into sample cup. Keep coughing up sputum until the cup is filled to the marker, which should equal approximately 1 teaspoon.
Screw the lid onto the cup and wash and dry the outside of it. Write name and the date on the label.
Take the sample to the clinic or laboratory, following instruction. You can refrigerate it for up to 24 hours if needed, but you shouldn’t freeze it or store it at room temperature.
LABORATORY EXAMINATION OF SPUTUM FOR GRAM’S STAINING -
Discovered by Dr. Hans Christian Gram in 1884, the Gram stain is a differential stain that is used in identifying bacteria. Dividing bacterial cells in two major groups (Gram positive and Gram negative), gram staining is an important test used because it can determine the presence of bacteria in a sample, as well as differentiate between the two-distinct bacteria species, which are gram-positive and gram-negative bacteria. This test also is especially important in medicine because the identification of the specific pathogen can help in the treatment of a bacterial infection, in emergency hours, I always teach Gram staining continues to be an important primitive test stood the test of time and continues to be the only rapid test in Bacteriology, in most developing countries
SENSITIVITY AND SPECIFICITY – The early chapters in immunology we all have learnt on sensitivity and septicity; however, we must learn to apply the same terms in reporting the results from a sputum examination. The sensitivity of a technique usually depends on the number of microorganisms in the specimen. Its specificity depends on how morphologically unique a specific microorganism appears microscopically or how specific the antibody or genetic probe is for that genus or species. For example, the sensitivity of Cram stains is such that the observation of two bacteria per oil immersion field (X 1,000) of a Gram-stained smear. of uncentrifuged urine is equivalent to the presence of ≥ 105 CFU/ml of urine. An increase in the sensitivity of a test is often accompanied by a decrease in specificity. For example, examination of a Gram-stained smear of sputum from a patient with pneumococcal pneumonia is highly sensitive but also highly nonspecific if the criterion for defining a positive test is the presence of any Gram-positive cocci. If, however, a positive test is defined as the presence of a preponderance of Gram-positive, lancet-shaped diplococci, the test becomes highly specific but has a sensitivity of only about 50 percent, here we all differ with many of our colleagues when the sensitivity of the test become 50% or less the observer variations differs, and lead to conflicts, The identification of most Gram-negative bacilli is far more complex and often requires panels of many tests for determining biochemical and physiologic characteristics. Here comes the importance of clinical Microbiologists who are in constant touch with clinicians can be able to make a better diagnosis. The sensitivity may also be affected by the stage of the disease at which the specimen is collected. No gram stain observations are final in majority of specimens to be supported by a GOOD CLINICAL HISTORY culturing on Media suiting the facilities in the laboratory and doing a Antibiograms for the optimal results in clinical care.
CAUTION – Every Clinical sample has many reasons to be infected with Parasites, Viruses, and Fungi however the Grams method of staining is simple, economical and faster if used with wisdom.
Ref Principles of Diagnosis John A. Washington. Medical Microbiology. 4th edition.
Dr.T.V.Rao MD Freelance Clinical Microbiologist and on line educator
Please contact on collaborative work
Email – doctortvrao@gmail.com
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