Cytokeratins are epithelial markers whose expression don't lose during malignant transformation.

CYFRA 21–1 is a cytokeratin 19 fragment soluble in serum and can use as a circulating tumour marker. Although expressed in all body tissues, it is significant in the lung, particularly lung cancer tissues.

CYFRA 21–1 is a sensitive and specific tumour marker of non-small-cell lung cancer (NSCLC), especially the squamous cell subtype.

It also reflects the extent of the disease and has an independent prognostic role along with performance status and disease stage in NSCLC.

In addition, detection of serum CYFRA 21 1 allows for identifying high-risk patients that may benefit from adjuvant chemotherapy and enables the early detection of progressive disease in recurrent NSCLC.

Additionally, CYFRA 21–1 describe as a valuable marker for oesophagal squamous cell carcinoma and therapy monitoring of bladder cancer.

The performance data of the CYFRA21-1 Rapid Quantitative Test Kit (CLIA)

Manufacturer SEKBIO

Parameter CYFRA21-1

Linearity 0.1-500 ng/ml

Detection limit 0.1 ng/ml

benchmark product Roche

Test principle and procedure CYFRA21-1: Add 10 μl of sample + 30 μl of Ra, incubation for 10 minutes cleaning, 30 μl of Rd incubation for 5 minutes. Wash with 200 μl of washing solution. Finally, add 100 μl of A + 100 μl of B.

Six point calibration test results

Sample Concentration( ng/ml)

RLU Average CV S/N

546.75 4,445,546 4,404,255 4,487,587 4,445,796 0.94% 4231.40

93.62 706,516 710,963 736,349 717,943 2.24% 683.32

9.57 69,190 68,756 68,034 68,660 0.85% 65.35

1.03 7,703 7,728 7,799 7,743 0.64% 7.37

0.11 1,703 1,727 1,553 1,661 5.68% 1.58

0.01 1,181 1,003 968 1,051 10.87% 1.00 

Precision

Sample RLU Concentration Sample RLU Concentration

1 6,482 0.76

75 552,944 72.72

5,679 0.72 564,704 74.21

6,317 0.80 563,241 74.03

5,976 0.77 558,522 73.43

6,211 0.82 570,900 75.00

5,873 0.81 566,827 74.48

6,055 0.79 545,138 71.72

6,028 0.79 573,240 75.30

5,927 0.82 550,118 72.36

6,166 0.84 555,993 73.10

AVE 6,71.40 0.79 AVE 560,162.70 73.63

SD 231.61 0.03 SD 9187.21 1.17

CV 3.8% 4.3% CV 1.6% 1.6%

Limit of detection

Sample RLU Concentration

Ag Diluent 1,108 1,164 0.025 0.016

1,124 1,128 0.019 0.019

1,024 1,037 0.003 0.001

1,103 1,103 0.015 0.015

1,055 1,090 0.013 0.007

1,118 1,043 0.004 0.018

1,094 1,183 0.029 0.013

1,040 1,082 0.011 0.004

947 918 0 0

1,054 1,110 0.016 0.006

AVE 1,076.25 0.01

SD 64.60 0.01

AVE+2*SD 0.028

Linear

Sample（ng/ml) Dilution ratio Concentration value Average

438.24 1.0 448.87 443.83 422.03 438.24

350.61 0.8 337.81 349.19 342.22 343.07

262.98 0.6 243.27 247.31 232.15 240.91

175.35 0.4 148.61 151.02 151.09 150.24

87.72 0.2 72.49 69.26 69.64 70.46

0.09 0.0 0.08 0.10 0.09 0.09 

Method Comparison

Reagents Stability

Reagent Sample(ng/ml) Average Deviation

2-8℃ 70.00 2,862,814

10.00 424,472

0.10 9,674

Antigen diluent 4,025

random sample 21,808

calf serum 4,816

37℃ 1d 70.00 2,717,873 -5.06%

10.00 415,759 -2.05%

0.10 9,322 -3.64%

Antigen diluent 4,062 0.91%

random sample 21,842 0.16%

calf serum 4,626 -3.96%

37℃ 3d 70.00 2,720,985 -4.95%

10.00 434,677 2.40%

0.10 9,822 1.52%

Antigen diluent 4,339 7.80%

random sample 22,399 2.71%

calf serum 4,965 3.09%

37℃ 7d 70.00 2,683,682 -6.26%

10.00 408,162 -3.84%

0.10 9,285 -4.02%

Antigen diluent 4,224 4.93%

random sample 23,879 9.49%

calf serum 5,120 6.31%

Cytokeratin 19 Fragment (CYFRA21-1) Products

Name Application

Mouse anti-human CYFRA21-1 mAb For immunodiagnostic: ELISA, LFA, CLIA

Humanized anti-human CYFRA21-1 mAb

CYFRA21-1 Intro

In malignant epithelial cells, the activated protease accelerates the degradation of the cells so that a large number of cytokeratin fragments are released into the blood, and the soluble pieces can specifically bind to the two monoclonal antibodies KS19.1 and BM19.21, so it is called CYFRA21 -1. In malignant lung cancer tissues, CYFRA21-1 is abundant, especially in lung squamous cell carcinoma.