Pathology
Showing 18 of 18 topics
A
-
Antimicrobial susceptibility testing translates organism growth in the presence of an antimicrobial into an MIC or zone diameter and then into an interpretive category using organism-, drug-, method-, and site-specific breakpoints. The MIC is not a direct dose recommendation and should never be compared numerically across unrelated drugs. Accurate interpretation requires current breakpoints, appropriate organism identification, validated methods, and integration with infection site and pharmacokinetics.
B
-
Blood culture performance depends more on correct patient selection, aseptic technique, and adequate blood volume than on drawing cultures at arbitrary time intervals. For adults with suspected bloodstream infection, multiple properly filled sets collected before antibiotics when feasible improve pathogen recovery and help distinguish true bacteremia from contamination. Cultures should never delay immediately necessary antimicrobial therapy in an unstable patient.
-
Breast core-biopsy reporting should establish histologic type and grade, invasive versus in situ disease, and predictive biomarkers on an adequate specimen. ER and PR are reported by validated immunohistochemistry, HER2 follows current ASCO/CAP IHC and ISH criteria, and results must be correlated with imaging, fixation quality, and the later surgical specimen when discordant.
C
-
The Bethesda System for cervical cytology standardizes specimen adequacy and epithelial-cell abnormalities, but management is no longer based on the Pap category alone. Current ASCCP guidance uses present HPV results plus prior screening, treatment, and age to estimate immediate and 5-year CIN3+ risk and determine whether the patient needs routine screening, surveillance, colposcopy, or treatment.
-
Mismatch-repair immunohistochemistry and microsatellite-instability testing identify colorectal cancers with deficient DNA mismatch repair, inform Lynch syndrome evaluation, provide prognostic information, and can predict benefit from immune checkpoint blockade. The key interpretive step is not merely calling a tumor dMMR or MSI-high, but using the loss pattern and clinical setting to determine appropriate reflex testing and germline assessment.
-
Colorectal polyp pathology should identify polyp type, size when available, dysplasia grade, villous component where relevant, completeness of excision when assessable, and invasive cancer features. Surveillance intervals are determined by the combination of pathology, number, size, bowel-preparation quality, and confidence in complete removal rather than by the word 'polyp' alone.
-
Cerebrospinal fluid interpretation depends on the clinical syndrome, opening pressure when relevant, cell count and differential, protein, glucose paired with serum glucose, microbiology, and targeted molecular or cytologic testing. No single CSF pattern is perfectly specific. The safest approach is to recognize high-risk patterns such as bacterial meningitis or subarachnoid hemorrhage while accounting for traumatic taps, prior antibiotics, immune status, and timing.
H
-
Hemolytic anemia is diagnosed by combining evidence of accelerated red-cell destruction with an assessment of marrow response and mechanism. No single laboratory result is sufficient. Reticulocytosis, indirect hyperbilirubinemia, elevated LDH, and reduced haptoglobin support hemolysis, while the peripheral smear and direct antiglobulin test help distinguish immune, microangiopathic, membranopathic, enzymatic, infectious, and mechanical causes.
L
-
Lung cancer resection pathology establishes tumor type, invasive size and extent, margin status, nodal involvement, treatment response when neoadjuvant therapy was given, and pathologic TNM category. A high-quality report follows the current College of American Pathologists lung cancer protocol and preserves enough tissue for clinically required biomarker testing.
-
Suspected lymphoma usually requires architecture plus immunophenotype and, when appropriate, cytogenetic or molecular studies. Excisional or adequately sized core biopsy is preferred over FNA alone when feasible. Tissue must be triaged prospectively so flow cytometry, histology, immunohistochemistry, FISH, and molecular studies can be performed without exhausting the specimen.
M
-
Screening for a monoclonal gammopathy should be driven by a compatible clinical problem rather than used as population-wide testing. For most suspected monoclonal proteins, serum protein electrophoresis combined with serum free light chains improves initial detection, and immunofixation characterizes a detected monoclonal protein. Interpretation must distinguish MGUS from smoldering or active plasma-cell disorders and recognize that renal dysfunction changes free-light-chain concentrations.
P
-
Peripheral blood smear review is a targeted extension of the complete blood count that can rapidly identify morphology suggesting hemolysis, marrow stress, hematologic malignancy, infection, or a laboratory artifact. It is most useful when the automated count is unexpected, flagged, internally inconsistent, or accompanied by a clinical syndrome in which cell morphology changes the differential or urgency.
-
An isolated prolonged activated partial thromboplastin time should be approached as a laboratory phenotype, not immediately labeled a bleeding disorder. A mixing study helps distinguish a factor deficiency from an inhibitor by testing whether patient plasma corrects when mixed with normal plasma. Interpretation requires attention to preanalytic error, heparin or direct anticoagulant exposure, immediate versus incubated results, reagent sensitivity, and the patient's bleeding or thrombosis history.
S
-
Solid-tumor molecular testing succeeds or fails partly at specimen triage. The pathology team must confirm diagnosis, preserve representative viable tumor, estimate tumor cellularity, choose the least destructive necessary ancillary tests, and match tissue to a validated molecular platform. A technically successful sequence run is not clinically useful if the sample is wrong, exhausted, poorly preserved, or interpreted without tumor context.
-
Surgical pathology accuracy begins before microscopy. Specimen identity, orientation, margin designation, cold ischemia time, fixation, and preservation of tissue needed for culture, flow cytometry, molecular testing, or frozen section must be planned at collection. Most routine surgical specimens go promptly into adequate neutral buffered formalin, but important exceptions require fresh, sterile, refrigerated, or specialized handling.
T
-
The Bethesda System for Reporting Thyroid Cytopathology standardizes FNA interpretation into six categories linked to approximate malignancy risk and typical management. The 2023 third edition refines terminology and risk estimates and incorporates modern molecular testing. Cytology must be interpreted together with ultrasound risk, nodule size, clinical history, and patient preference.
-
Pretransfusion testing is designed to identify the recipient's ABO/RhD type, detect clinically significant red-cell antibodies, and demonstrate compatibility between the patient and the selected component. A type and screen is often sufficient when transfusion is only possible, while a crossmatch is performed when red cells are being assigned. Emergency bleeding can require uncrossmatched blood before testing is complete, followed by rapid transition to type-compatible components.
U
-
Urinalysis and urine microscopy become clinically powerful when dipstick chemistry is interpreted together with sediment findings, specimen quality, kidney function, and the pretest probability of infection or glomerular disease. The most useful abnormalities are pattern based: dysmorphic erythrocytes and red cell casts suggest glomerular bleeding, white cell casts suggest renal parenchymal inflammation, granular casts support tubular injury, and crystals must be interpreted in the appropriate clinical cont
No topics match your filters.