The chromosome examination was performed by using peripheral blood under the action of phytoagglutinin (PHA), a cell growth stimulating factor, for 72 hours at 37°C to obtain a large number of dividing cells, and then adding colchicine to stop the dividing cells at mid-division to facilitate the observation of chromosomes. Finally, the cells were fixed on slides with methanol and glacial acetic acid, and the structure and number of chromosomes were observed under the microscope. The karyotype of a normal male is 44 autosomes plus 2 sex chromosomes, X and Y. This is often expressed as 46, XY in the examination report. Normal females have the same autosomes as males and 2 sex chromosomes, XX, 46, XX. 46 indicates the total number of chromosomes, greater than or less than 46 is considered an abnormal number of chromosomes. Missing sex chromosomes are often indicated by O. Chromosome test cost: The cost of chromosome test varies around the world, generally between 300-500. Clinical indications for chromosome examination: 1. Patients with leukemia and other tumors Chromosome abnormalities that occur in leukemia and other tumors can cause the expression of oncogenes in blood cells, resulting in uncontrolled malignant growth of blood cells. Different leukemias often have their own characteristic chromosomal abnormalities, so chromosomal examination can help in the diagnosis and prognosis determination of leukemia. (1) Acute lymphoblastic leukemia: chromosomal examination may reveal mutual translocation of chromosomes 8 and 14, mutual translocation of chromosomes 4 and 11, six abnormal chromosomes formed by mutual translocation of chromosomes 9 and 22 and an additional chromosome 21. (2) Acute myeloid leukemia: chromosomal alterations are mainly mutual translocations of chromosomes 8 and 21, and mutual translocations of chromosomes 15 and 17, resulting in 4 abnormal chromosomes. (3) Chronic granulocytic leukemia: Ph chromosome is the marker chromosome, formed by the translocation of chromosomes 9 and 22, and the appearance of Ph chromosome is an indicator of the diagnosis of chronic granulocytic leukemia. If the original fragments of chromosomes are not rejoined in the original position after the chromosome split, various chromosomes with abnormal structure will be formed, such as deletion, translocation, inversion, repetition, ring chromosome, etc. These aberrations can cause some corresponding diseases, such as tumors, if they occur in somatic cells. If these aberrations occur in germ cells, they can have genetic effects and affect the offspring, causing miscarriage, stillbirth and malformed children. 3, secondary sex characteristics abnormalities Commonly found in women, such as primary amenorrhea, sexual dysplasia, with short stature, elbow ectropion, shield chest and slightly low intelligence, little or no pubic hair, axillary hair, low posterior hairline, sterility, etc., should consider whether there is an X chromosome abnormality. The common X chromosome abnormalities are Turner’s syndrome and circular X chromosome. Patients with Turner’s syndrome have one fewer X chromosome than normal women, with a karyotype of 45, XO. Patients with ring X chromosomes have a break in both ends of the X chromosome for some reason and rejoin at the site of the break to form a ring. The smaller the ring chromosome, the more severe the clinical symptoms. Early detection of these abnormalities and appropriate treatment can improve the secondary sexual characteristics to a certain extent, and may also gain fertility. For patients with ambiguous differentiation of external genitalia, such as penis with hypospadias, clitoral hypertrophy in the form of penis, it is often difficult to correctly determine the gender according to the appearance of genitalia, the examination of sex chromosomes can help to make a clear diagnosis. 5. Sexual abnormalities Some men who are tall, aggressive and have aggressive behavior may be sex chromosome abnormalities. The majority of patients have a normal phenotype, i.e., good health, and are often fertile, but the chance of having a male offspring with the same 47,XYY is greater than in the normal population. The prevalence of the disease is 1 in 750 in the general male population, and men with elongated stature, slender limbs, small penis, undeveloped testes and absence of sperm in the semen, sometimes accompanied by mental abnormalities, should be examined by chromosomal examination to determine if they have Cox’s syndrome, which has one more X chromosome than normal males and a karyotype of 47,XXY. /The prevalence is 1 in 800 men, 1 in 1 percent of men with mental retardation, and up to 1 in 10 men with infertility. 6. Reproductive dysfunction At least 7-10 percent of women with reproductive dysfunction, such as infertility, multiple abortions, and malformations, are carriers of chromosomal abnormalities. The chromosomal abnormalities include structural abnormalities such as balanced translocations and inversions and quantitative abnormalities such as 45,XO in women with one less X chromosome or 47XXY in women with one more Y chromosome. balanced translocations and inversions do not cause disease in the carriers themselves because there is no gene loss, but the chromosomal abnormalities in their germ cells can lead to infertility, miscarriage and abnormal fetuses and other reproductive dysfunctions. The abnormal number of sex chromosomes can cause infertility and often abnormal secondary sex characteristics. 7. Premarital examination Premarital examination can find abnormal chromosome carriers with normal phenotypes, such as chromosome balanced translocations and inversions, and chromosome balanced translocations and inversions with no loss of genes and normal phenotypes, but they are very likely to cause miscarriage, abnormality and stillbirth, and blind birth control will increase the birth rate of abnormal children. The premarital examination can also find people with normal phenotypes but sex chromosome abnormalities, which can be manifested as sexual dysfunction and infertility. Therefore, premarital examination has an important significance for eugenics. The common clinical features include small head, thin and fine hair, wide eye spacing, low ear position, short neck, collapsed and short nose, hypoplastic external genitalia, cleft palate, hypo- or hyper-myotonia, epilepsy, through palm, anal atresia, short stature, growth retardation, small eye fissures, low hairline, persistent neonatal jaundice and marked cyanosis, ptosis, cardiac malformations, renal malformations, and iris or retinal defects. Chromosomal examination may reveal abnormalities such as trisomy 21.