The auxiliary judgment bases for different typologies of psoriasis are different, and need to be considered through the change patterns of blood-related indicators and special indicators and their clinical significance.
Blood-related indexes: white blood cell count, neutrophils, erythrocyte sedimentation rate.
Special indicators: anti-streptococcal hemolysin O, C-reactive protein, rheumatoid factor.
Psoriasis includes common psoriasis, pustular psoriasis, erythrodermic psoriasis and arthritic psoriasis, and different types have different auxiliary judgment bases.
Blood tests
The clinic needs to provide more typing basis for the laboratory examination of psoriasis through the change pattern of blood-related indicators and special indicators.
So, what is the normal range of each index in the examination results?
White blood cell count: the normal range of white blood cells for adults in general is (4.0-10.0) × 10^9/L; for children, it is (5.0-12.0) × 10^9/L.
Neutrophils: normal value is (1.8-6.3)x10^9/L.
Erythrocyte sedimentation rate: also called hematocrit, normal value is 0-15mm/h for males and 0-20mm/h for females.
Anti-streptococcal hemolysin O: normal reference value ≤250 units (U), latex agglutination method <500 units (U).
C-reactive protein: normal reference value <12.5ng/ml; immune one-way diffusion method <10mg/L.
Rheumatoid factor: normal value is negative.
When these indicators are not normal, what does each of them mean?
White blood cell count: an increase in white blood cells may be a bacterial infection; a decrease in white blood cells may be a viral infection.
Neutrophil: pathologically increased is mainly seen in bacterial infections, especially septicoccus is most common; pathologically decreased is commonly seen in viral infections and hematologic disorders.
Erythrocyte sedimentation rate: It refers to the sedimentation distance of red blood cells under certain conditions and in a unit time, referred to as hematocrit. In addition to some physiological factors, where there is infection or necrotic tissue in the body, the hematocrit can be accelerated, suggesting the presence of lesions, and the decrease in hematocrit has no clinical significance.
Anti-streptococcal hemolysin O: It is used for the auxiliary diagnosis and course monitoring of rheumatic fever, acute glomerulonephritis, erythema nodosum, scarlet fever, acute tonsillitis and other diseases caused by suspected group A streptococcal infection. Elevated anti-streptococcal hemolysin O is mostly indicative of streptococcal infection, and decreased without clinical significance.
C-reactive protein: C-reactive protein is often used to understand the activity of acute rheumatic fever and rheumatoid arthritis, and can also be used as an indicator to evaluate the effectiveness of treatment regimens. The degree of active C-reactive protein elevation may reflect the size or activity of the inflammatory tissue. C-reactive protein is also increased in the presence of concurrent bacterial infections, and a decrease in C-reactive protein is not clinically significant.
Rheumatoid factor: Positive rheumatoid factor is common in rheumatoid arthritis, but negative rheumatoid factor does not exclude the diagnosis of rheumatoid arthritis.
What do the index changes in the test results indicate for different types of psoriasis?
Psoriasis vulgaris: laboratory tests reveal elevated white blood cell counts and neutrophil ratios, and elevated anti-streptococcal hemolysin O titers, which can indicate the presence of inflammatory infections.
Pustular psoriasis: laboratory tests can reveal increased peripheral blood leukocytes or increased neutrophils, accelerated erythrocyte sedimentation rate, and may include hypoproteinemia and hypocalcemia.
Erythrodermic psoriasis: changes such as increased total leukocyte count, absolute neutrophil value and absolute monocyte value, increased erythrocyte sedimentation rate and elevated C-reactive protein can be seen.
Arthritic psoriasis: laboratory tests reveal elevated C-reactive protein and accelerated erythrocyte sedimentation rate. HLA-B27 is often positive and rheumatoid factor is often negative in those with spine or sacroiliac joint involvement, which can be differentiated from rheumatoid arthritis.
References
[1]Chinese psoriasis treatment guidelines (2018 short version) [J]. Chinese Journal of Dermatology,2019(04):223-230.
[2]Lin Songyuan. How to read the medical examination report form. 3rd edition [M]. Fuzhou:Fujian Science and Technology Press,2019(01):253-258.
[3] Zhang XC et al. eds. Clinical testing techniques and clinical applications [M]. Shanghai:Shanghai Jiaotong University Press,2018(06):88-90.