Raynaud’s phenomenon (RP) is also known as Raynaud’s syndrome. It is characterized by a triphasic reaction of pallor, grouping and flushing, mostly in the upper extremities, symmetrical on both sides, or involving the lower extremities, or both upper and lower extremities, and occasionally in the ears, nose, cheeks or collar. It is often triggered by cold or emotional excitement. During the attack, the fingers become cold, the skin is obviously pale and stiff, and even the fingers have difficulty moving, and there is a numbness and pins and needles sensation, then the color deepens to dark red or greenish purple, and in severe cases, some of the nails are also grouped, after which the skin color becomes lighter, diffuse flushing, and the throbbing sensation increases, and finally returns to normal. The repeated occurrence of Raynaud’s phenomenon can cause local ulceration, atrophy, sclerosis and gangrene. However, it is more common to see various nutritional changes in the fingers (toes), often with pointed or lemon shaped finger ends, and the nails can be twisted and deformed. Raynaud’s phenomenon can be divided into two types: primary and secondary. The former is of unknown etiology and is a benign spasm of the small arteries of the extremities, also known as Raynaud’s disease, mostly seen in women. The latter is secondary to other diseases, i.e. Raynaud’s phenomenon manifests in other diseases. Recent studies have shown that Raynaud’s phenomenon not only affects the extremities, but can also occur in the viscera of patients with connective tissue diseases, mainly involving the lungs, heart, brain, and kidneys, with varying reports as to whether Raynaud’s phenomenon can cause damage to internal organs. What are the tests for pale, grouped and flushed extremities one after another? 1.Cold water stimulation test Ask the patient to sit quietly in a warm room for 20-30min, then immerse the hands or feet in 4℃ ice water, about l-2min can observe local pale skin color, 2-5min after leaving the water, the skin color becomes purple and flushed, and accompanied by local cold, numb, pins and needles-like pain, the attack lasts for several minutes and then stops. This method can estimate the extent of the disease and the effectiveness of treatment. It is more commonly used in China. 2, nail wrinkle capillaroscopy can be seen in patients with capillary mu anomalies, rand top bruising, dark red blood color, plasma exudation tube rand bleeding, slowed blood flow, abnormal flow pattern. This is not seen in normal people. This method is commonly used in China to detect. 3.Laser Doppler flowmeter Laser fiber launched into the skin (about 1mm below the surface of the skin photons encountered within the microcirculation of moving red blood cells, its frequency changes, the light emitted back by the skin is collected, converted into a signal is displayed, the blood flow rate and flow can be calculated, China has not seen the detection of this method reported. 4.Radionuclide measurement The radionuclide 131I sodium can be used to determine the nutritional blood flow of the affected finger. 5.Microcirculation microscope Foreign countries have been able to show the intracutaneous capillaries on the TV screen, directly record the flow rate and flow, but also can be inserted into the capillary network of the out, people rub, the determination of pressure changes. 6.Volume and photoelectric volumetric tracers Measure the increase and decrease value of the annular surface of the affected finger, as well as detect the finger arterial pulsation, etc. to estimate the change of blood flow, the decrease of blood flow of the affected finger and the decrease of the amplitude of the arterial pulsation. 7, upper extremity arteriography After the first imaging, the hand is immersed in ice water for 20 seconds, dried and re-imaged once more. In addition to the spasm of the affected finger artery, the larger metacarpal artery and even the forearm artery can be involved. 8, cold agglutinin antibodies Some patients can be present in the serum cold agglutinin, this antibody at 15-20 ℃ and the red blood cell membrane glycoprotein I/i antigen binding agglutination, and then lysis of red blood cells, 37 ℃ can be dissociated, mostly IgM, normal human serum condensation potency of 1: 32 or less, Raynaud’s disease cold agglutinin potency of up to 1: 128, but this test is not specific, many Cold agglutinin can also be detected in many other diseases. Such as viral pneumonia, infectious mononucleosis, rubella, lymphoma, systemic lupus erythematosus, etc. 9, cold globulinemia Can cause plasma precipitation reaction at 4 ℃, above 37 ℃ dissolved. Normal human plasma fibrinogen is 2-4g/L, while it can exceed this value in Raynaud’s disease. It can also be present in patients with extremity cyanosis, reticulocytosis, cold ischialgia, and paroxysmal cold hemoglobinuria. Significant cold globulinemia is seen only in multiple myeloma. 10. Other antibodies Due to immune dysfunction, patients with Raynaud’s phenomenon have higher serum RNP antibodies and anti-Sm antibodies (antibodies to a nucleoprotein peptide linked to RNA), blood gamma-globulin, IgG levels, and circulating immune complexes than patients without Raynaud’s phenomenon.