What Is a 9-Line MEDEVAC? Format, MIST Report, and CASEVAC

A 9-line MEDEVAC is a standardized nine-item radio message used to request medical evacuation for wounded or sick personnel during military operations. The format works for both air and ground evacuation, is governed by Army Techniques Publication 4-02.2, and is designed to be transmitted in under 25 seconds so an aircraft or ambulance can launch on the first five lines while the rest of the information follows en route.

When It Gets Called

A 9-line goes out whenever a casualty needs a higher level of medical care and routine transport cannot deliver it in time. Combat wounds from blasts or gunfire are the classic case, but the format covers acute medical emergencies like cardiac events or severe allergic reactions, vehicle rollovers, falls, and training accidents. The environment matters as much as the injury itself. In combat zones, disaster-response operations, and isolated forward operating bases, roads may be unusable and dedicated medical facilities may be hours away, so even a moderately serious condition can turn life-threatening without a dedicated evacuation.

The Nine Lines

Line numbers never change, and the format is the same across every branch. A few lines carry different content in wartime than in peacetime, noted below.

Lines 1 Through 5: What Launches the Aircraft

The first five lines are transmitted during the initial radio call because they contain everything the evacuation crew needs to get moving.¹

Line 1 — Location of the pickup site. Grid coordinates, typically in Military Grid Reference System (MGRS) format. Encrypted in transmission so the enemy cannot identify the site.
Line 2 — Radio frequency and call sign. The frequency and call sign of the person on the ground the incoming crew will talk to. The call sign can go in the clear; the frequency is encrypted.
Line 3 — Number of patients by precedence. How many casualties and how urgently each needs evacuation. The five categories are Urgent (within 2 hours), Urgent Surgical (within 2 hours, requires surgery), Priority (within 4 hours), Routine (within 24 hours), and Convenience (no specific time constraint).²
Line 4 — Special equipment required. Hoist (for sites where the aircraft cannot land), extraction equipment, or a ventilator. If nothing extra is needed, the requestor reports “none.”
Line 5 — Number of patients by type. How many can walk (ambulatory) and how many need a stretcher (litter). This determines cabin configuration and how many attendants come along.

Lines 6 Through 9: What Follows En Route

These four lines can be sent while the platform is already moving. They give situational awareness rather than launch-critical data.

Line 6 — Security at the pickup site (wartime) or number and type of wounded (peacetime). In combat, four codes describe the threat: no enemy present, possible enemy, enemy in the area with caution advised, or enemy in the area with an armed escort required. That last code means a weapons platform will need to accompany the MEDEVAC aircraft. In peacetime, this line describes the casualties instead.¹
Line 7 — Method of marking the pickup site. Colored panels, pyrotechnic signals, or smoke are common. If none are available, the requestor reports “none” or “other” and coordinates verbally.
Line 8 — Patient nationality and status. U.S. military, U.S. civilian, non-U.S. military, non-U.S. civilian, or enemy prisoner of war. This affects which facility receives the patient and what paperwork follows.
Line 9 — NBC contamination (wartime only). Whether nuclear, biological, or chemical contamination is present. Included only when contamination actually exists, so the crew brings protective equipment or decontamination capability.²

How the Request Is Transmitted

The requestor contacts the unit controlling evacuation assets, announces “I have a MEDEVAC request,” and waits one to three seconds for acknowledgment. If no one responds, the statement gets repeated.¹

Lines 1 through 5 go out on that initial contact because they contain everything needed to launch. Lines 6 through 9 can follow while the platform is already en route. The whole transmission should take no more than 25 seconds. Every element except the call sign in Line 2 is encrypted using the unit’s signal operating instructions, and letters and numbers follow standard radio telephone pronunciation to cut down on misheard information.

Once the medical evacuation control center has the request, it matches precedence and special equipment needs against available assets. An urgent surgical case gets a different response than a routine evacuation. The receiving unit stays on the radio with the requestor, relaying estimated arrival times and any changes to the plan, and the requestor keeps monitoring for further instructions.

The MIST Report That Goes With It

The 9-line tells the crew where to go and what to bring. It says almost nothing about what happened to the patient. That gap is filled by the MIST report, a brief verbal handoff given for each casualty at the conclusion of the 9-line.³

Mechanism — what caused the injury: blast, gunshot, vehicle collision.
Injuries — where the damage is and what it looks like, often combined with mechanism, as in “gunshot wound to the left leg.”
Signs and symptoms — what the medic sees now: severe bleeding, no radial pulse, abnormal breathing, altered consciousness.
Treatment — what has already been done: tourniquets, airway placement, medications administered.

The MIST report gives the arriving medical crew a head start. Instead of assessing the patient from scratch, they arrive knowing the injury pattern, current vital signs, and interventions already in place.

MEDEVAC Is Not the Same as CASEVAC

The 9-line format is built for MEDEVAC specifically, not for every casualty movement. A MEDEVAC uses dedicated, properly marked medical platforms with trained medical personnel providing care during transport. A CASEVAC moves casualties aboard nonmedical vehicles or aircraft with no en route medical care.⁴

The distinction has real consequences. Under the Geneva Conventions, medical aircraft receive protected status when used exclusively for transporting the wounded and sick, provided they are unarmed and fly at heights, times, and routes agreed upon by the parties to the conflict.⁵ A CASEVAC platform, whether a patrol vehicle, a cargo helicopter, or whatever transport is available, has no such protection and carries no medical personnel. Commanders weigh that tradeoff constantly, and the 9-line exists for the MEDEVAC side of it.

Why the Format Is Built for Speed

The whole 9-line system revolves around what military medicine calls the golden hour, the first 60 minutes after severe trauma. Historical wound data shows that more than 90 percent of combat fatalities who do not receive advanced care die within that first hour, with roughly two-thirds dying in the first 30 minutes.⁶

That timeline shapes every design choice in the format. The 25-second transmission limit, the split that lets the aircraft launch on lines 1 through 5 before the rest arrive, the single-letter brevity codes, and the two-hour Urgent and Urgent Surgical windows on Line 3 all exist to compress the gap between injury and surgical care.¹

1
U.S. Army. Appendix J – 9-LINE MEDEVAC REQUEST
2
Missouri Western State University. MEDEVAC Request Form GTA 08-01-004
3
TCCC. 9-Line MEDEVAC and MIST Preparation
4
Line of Departure – U.S. Army. MEDEVAC vs CASEVAC – Life Saving Decisions in the Field Artillery
5
International Committee of the Red Cross. Commentary of 1958 – Convention IV, Article 22
6
Defense Technical Information Center. The Golden Hour Standard – Transforming Combat Health Support