Clinical value of serum amyloid A(SAA)
The change of SAA level has important clinical value for early diagnosis, risk assessment, curative effect observation and prognosis evaluation of infectious diseases.
Infectious diseases are common types of diseases in clinic. Infectious diseases are characterized by various pathogens, diverse infection routes and individual differences in symptoms and signs, which can lead to serious consequences if they are not diagnosed and treated effectively in time. Therefore, how to make early diagnosis and/or differential diagnosis of infectious diseases is a practical problem that needs to be solved urgently in clinic.
A(serum amyloid A (SAA) is a nonspecific acute phase reaction protein, and its clinical value as a marker of inflammation has been widely concerned in recent years.The change of SAA level has important clinical value for early diagnosis, risk assessment, curative effect observation and prognosis evaluation of infectious diseases.In addition to the increase in bacterial infection, SAA is also significantly increased in viral infection. According to the degree of increase or combined with other indicators, bacterial or viral infection can be indicated, thus making up for the deficiency that commonly used inflammatory markers can not indicate viral infection at present.
Clinical significance of SAA
1, rapid diagnosis of bacterial infection and virus infection;
2. SAA is more sensitive than CRP in the early stage of infection and weak inflammatory stimulation, which can provide better differentiation;
3. Sensitive reaction, which can be used as a sensitive index to reflect infection and inflammation control;
4. It is widely used in auxiliary diagnosis of infectious diseases, risk prediction of coronary heart disease, dynamic monitoring of curative effect and prognosis of tumor patients, monitoring of transplant rejection and monitoring of improvement of rheumatoid arthritis;
5. The combined detection of SAA, CRP and PCT can better reflect the complementary advantages, provide another basis for the diagnosis and differential diagnosis of bacterial and viral infections, and better reflect the clinical value-added significance that can not be reflected by single indicators;
6. SAA combined with CRP can provide powerful data for the differential diagnosis of early bacterial and viral infections and guide the use of antibiotics;
7. Especially in the early diagnosis of infectious diseases in children and neonatal septicemia, it is more significant than single diagnosis in the early identification of bacterial and viral infections in infectious diseases in infants;
8. The increase of SAA and hs-CRP concentration may be positively correlated with the prediction of the risk of cardiovascular events in healthy people in the future, and the increase of both indexes is more significant for predicting the risk of cardiovascular events.
Clinical interpretation of SAA level
Summary of applicable departments, indications and clinical application of SAA
SAA is widely used in auxiliary diagnosis of infectious diseases, risk prediction of coronary heart disease, dynamic observation of curative effect and prognosis of tumor patients, observation of transplant rejection and observation of improvement of rheumatoid arthritis. Clinically, SAA concentration < 10 mg/L is normal, which is consistent with CRP reference range.
Early diagnosis of virus infection：SAA will increase rapidly in both bacterial and viral infections.CRP will only increase when there is bacterial infection. Based on this feature, the combined detection of SAA and CRP is more unique than that of CRP alone.For example, in two cases of fever caused by physical factors and cold caused by virus infection, CRP may be normal, and if SAA is increased, it may indicate that virus infection tends to increase.
Early diagnosis of bacterial infection;SAA index is more sensitive than CRP in early infection,It rises earlier and falls faster and more sharply when it recovers.In the early stage of infection, weak inflammatory stimulation SAA is more sensitive than CRP and can provide better differentiation.
Differential diagnosis between bacterial infection and virus infection;Simultaneous detection of both can provide powerful data for differential diagnosis of early bacterial and viral infections. Especially in the early diagnosis of infectious diseases in children and neonatal septicemia, it is more significant than single diagnosis in the early identification of bacterial and viral infections in infants and young children. As written in Laboratory Medicine, Volume 5, No.32, May 2017, Application of Serum Amyloid A and C-reactive Protein Detection in the Diagnosis of Infectious Diseases in Children:Combined detection of CRP and SAA can determine the type of infection more quickly and accurately, and provide effective laboratory basis for early diagnosis and follow-up treatment of diseases!
Risk predictors of cardiovascular and cerebrovascular events:The increase of SAA and hs-CRP concentration may be positively correlated with predicting the risk of cardiovascular events in healthy people in the future.The increase of both indexes is more significant for predicting the risk of cardiovascular events.
Tumor severity and prognostic evaluation index：SAA in patients with many tumors, such as liver cancer, lung cancer, breast cancer, prostate cancer, endometrial cancer, etc., has increased to varying degrees.SAA level has obvious correlation with the active stage, malignant degree and metastasis of tumor, and the metastasis stage of malignant tumorSAAElevations usually show higher values than those in the stable phase of tumors.Therefore, SAA, as a non-specific index, can be used as an index for dynamic observation of curative effect and prognosis of tumor patients.
Preferred indicators for monitoring graft rejection;The change of SAA concentration is a very sensitive index for transplant rejection. Studies show that 97% of renal transplant rejection is based on the increase of SAA, while the CRP concentration changes little.thereforeSAA concentration can be used as the first choice to monitor rejection.
Infection/Inflammation Solutions
The combined detection of SAA, CRP and PCT can effectively distinguish bacterial infection from viral infection, predict the risk of cardiovascular events and evaluate the prognosis of tumor diseases.
Comparison of three markers
