Thank you for sharing your heart so honestly as you wait for this blood test. Waiting is difficult, and the Lord hears your prayer and sees your trust in Jesus alone. That trust is the right place to stand.
Your hope before God is not built on anything you have done or can do, but on the finished work of Jesus Christ. His blood and His righteousness are the foundation for your standing with God. You can lean fully on His name, even while you are painfully aware of your own weakness and imperfection. He is able to do for you what you cannot do for yourself.
Scripture teaches that the life is in the blood, and God gave the blood upon the altar to make atonement for our souls. Without the shedding of blood there is no forgiveness of sin. That is why the reverence God taught His people to have for blood points us to something far greater, the blood of Jesus Himself. He did not enter the presence of God with the blood of animals, but with His own blood, offering Himself without spot, and He entered once for all into heaven itself to obtain eternal redemption for us. Because of that one offering, you have open access to come to the Father right now, in your worry and waiting, through Jesus.
All of the blessings God gives come by His grace, not as a reward we earn. God is always the one who initiates toward us in love, and we respond to what He has already given. There is no work you can offer that makes God respond to you. Instead you can simply rest in Him, believing and trusting Him to do what He has promised, not because you have earned it, but as a gift of His love and grace. That rest is where peace is found, even while you wait.
God knows the thoughts and intents of the heart. He knows your anxiety, your hope for a favorable outcome, and your desire to trust Him whatever the result may be. Faith that simply trusts Him is what pleases Him. Without faith it is impossible to please God, but when you put your trust in Him and commit your way to Him, He is pleased. Learning to know Him more helps that trust to grow, because when you know His character and His faithfulness, you find you can rest in Him rather than relying on human strength or trying to find a way to make things happen yourself.
The way home to God has been marked by blood, and Jesus has opened it for you. You can bring this burden to Him just as you are.
I am praying with you now. Father, in the name of Jesus, I bring this dear one and this loved one awaiting test results to You. You know the outcome and You love them both deeply. I ask that You would grant Your peace that guards heart and mind in Christ Jesus as they wait. I ask for Your mercy and grace over this blood test, and that You would work for good in whatever the result may be. If it is Your will, grant a favorable report and restore health, and in all things draw them closer to Yourself and show them Your care. Help them to continue to rest in the completed work of Jesus and to know that they are heard because of His blood. Purge their conscience from fear and striving and help them to serve and trust You with a quiet heart. In Jesus name, Amen.
Keep leaning on Jesus. He is with you in this waiting, He has made the way for you through His own blood, and He will continue to work in you both to will and to do according to His good purpose.